Amir Safavi-Naeini

All Publications

• Roles of temperature, materials, and domain inversion in high-performance, low-bias-drift thin film lithium niobate blue light modulators OPTICS EXPRESS Celik, O., Ammar, N., Park, T., Stokowski, H. S., Multani, K. S., Hwang, A. Y., Gyger, S., Guo, Y., Fejer, M. M., Safavi-Naeini, A. H. 2024; 32 (21): 36160-36170

  View details for DOI 10.1364/OE.538150

  View details for Web of Science ID 001334550200010

• Vacuum Beam Guide for Large Scale Quantum Networks. Physical review letters Huang, Y., Salces-Carcoba, F., Adhikari, R. X., Safavi-Naeini, A. H., Jiang, L. 2024; 133 (2): 020801

  Abstract

  The vacuum beam guide (VBG) presents a completely different solution for quantum channels to overcome the limitations of existing fiber and satellite technologies for long-distance quantum communication. With an array of aligned lenses spaced kilometers apart, the VBG offers ultrahigh transparency over a wide range of optical wavelengths. With realistic parameters, the VBG can outperform the best fiber by 3 orders of magnitude in terms of attenuation rate. Consequently, the VBG can enable long-range quantum communication over thousands of kilometers with quantum channel capacity beyond 10^{13}  qubit/sec, orders of magnitude higher than the state-of-the-art quantum satellite communication rate. Remarkably, without relying on quantum repeaters, the VBG can provide a ground-based, low-loss, high-bandwidth quantum channel that enables novel distributed quantum information applications for computing, communication, and sensing.

  View details for DOI 10.1103/PhysRevLett.133.020801

  View details for PubMedID 39073959

• Studying phonon coherence with a quantum sensor. Nature communications Cleland, A. Y., Wollack, E. A., Safavi-Naeini, A. H. 2024; 15 (1): 4979

  Abstract

  Nanomechanical oscillators offer numerous advantages for quantum technologies. Their integration with superconducting qubits shows promise for hardware-efficient quantum error-correction protocols involving superpositions of mechanical coherent states. Limitations of this approach include mechanical decoherence processes, particularly two-level system (TLS) defects, which have been widely studied using classical fields and detectors. In this manuscript, we use a superconducting qubit as a quantum sensor to perform phonon number-resolved measurements on a piezoelectrically coupled phononic crystal cavity. This enables a high-resolution study of mechanical dissipation and dephasing in coherent states of variable size ( n ¯ ≃ 1 - 10 phonons). We observe nonexponential relaxation and state size-dependent reduction of the dephasing rate, which we attribute to TLS. Using a numerical model, we reproduce the dissipation signatures (and to a lesser extent, the dephasing signatures) via emission into a small ensemble (N = 5) of rapidly dephasing TLS. Our findings comprise a detailed examination of TLS-induced phonon decoherence in the quantum regime.

  View details for DOI 10.1038/s41467-024-48306-0

  View details for PubMedID 38862502

  View details for PubMedCentralID PMC11167028

• A parametrically programmable delay line for microwave photons. Nature communications Makihara, T., Lee, N., Guo, Y., Guan, W., Safavi-Naeini, A. 2024; 15 (1): 4640

  Abstract

  Delay lines that store quantum information are crucial for advancing quantum repeaters and hardware efficient quantum computers. Traditionally, they are realized as extended systems that support wave propagation but provide limited control over the propagating fields. Here, we introduce a parametrically addressed delay line for microwave photons that provides a high level of control over the stored pulses. By parametrically driving a three-wave mixing circuit element that is weakly hybridized with an ensemble of resonators, we engineer a spectral response that simulates that of a physical delay line, while providing fast control over the delay line's properties. We demonstrate this novel degree of control by choosing which photon echo to emit, translating pulses in time, and even swapping two pulses, all with pulse energies on the order of a single photon. We also measure the noise added from our parametric interactions and find it is much less than one photon.

  View details for DOI 10.1038/s41467-024-48975-x

  View details for PubMedID 38821933

  View details for PubMedCentralID 5664532

• Quantum control and noise protection of a Floquet 0-π qubit PHYSICAL REVIEW A Wang, Z., Safavi-Naeini, A. H. 2024; 109 (4)

  View details for DOI 10.1103/PhysRevA.109.042607

  View details for Web of Science ID 001222320000004

• Picojoule-level supercontinuum generation in thin-film lithium niobate on sapphire OPTICS EXPRESS Hamrouni, M., Jankowski, M., Hwang, A. Y., Flemens, N., Mishra, J., Langrock, C., Safavi-Naeini, A., Fejer, M. M., Sudmeyer, T. 2024; 32 (7): 12004-12011

  Abstract

  We demonstrate ultraviolet-to-mid-infrared supercontinuum generation (SCG) inside thin-film lithium niobate (TFLN) on sapphire nanowaveguides. This platform combines wavelength-scale confinement and quasi-phasematched nonlinear interactions with a broad transparency window extending from 350 to 4500 nm. Our approach relies on group-velocity-matched second-harmonic generation, which uses an interplay between saturation and a small phase-mismatch to generate a spectrally broadened fundamental and second harmonic using only a few picojoules of in-coupled fundamental pulse energies. As the on-chip pulse energy is increased to tens of picojoules, these nanowaveguides generate harmonics up to the fifth order by a cascade of sum-frequency mixing processes. For in-coupled pulse energies in excess of 25 picojoules, these harmonics merge together to form a supercontinuum spanning 360-2660 nm. We use the overlap between the first two harmonic spectra to detect f-2f beatnotes of the driving laser directly at the waveguide output, which verifies the coherence of the generated harmonics. These results establish TFLN-on-sapphire as a viable platform for generating ultra-broadband coherent light spanning from the ultraviolet to mid-infrared spectral regions.

  View details for DOI 10.1364/OE.514649

  View details for Web of Science ID 001299830400001

  View details for PubMedID 38571035

• Surface modification and coherence in lithium niobate SAW resonators. Scientific reports Gruenke, R. G., Hitchcock, O. A., Wollack, E. A., Sarabalis, C. J., Jankowski, M., McKenna, T. P., Lee, N. R., Safavi-Naeini, A. H. 2024; 14 (1): 6663

  Abstract

  Lithium niobate is a promising material for developing quantum acoustic technologies due to its strong piezoelectric effect and availability in the form of crystalline thin films of high quality. However, at radio frequencies and cryogenic temperatures, these resonators are limited by the presence of decoherence and dephasing due to two-level systems. To mitigate these losses and increase device performance, a more detailed picture of the microscopic nature of these loss channels is needed. In this study, we fabricate several lithium niobate acoustic wave resonators and apply different processing steps that modify their surfaces. These treatments include argon ion sputtering, annealing, and acid cleans. We characterize the effects of these treatments using three surface-sensitive measurements: cryogenic microwave spectroscopy measuring density and coupling of TLS to mechanics, X-ray photoelectron spectroscopy and atomic force microscopy. We learn from these studies that, surprisingly, increases of TLS density may accompany apparent improvements in the surface quality as probed by the latter two approaches. Our work outlines the importance that surfaces and fabrication techniques play in altering acoustic resonator coherence, and suggests gaps in our understanding as well as approaches to address them.

  View details for DOI 10.1038/s41598-024-57168-x

  View details for PubMedID 38509245

• Efficient parametric down-conversion by gain-trapped solitons OPTICA Hamrouni, M., Jankowski, M., Hwang, A. Y., Jornod, N., Mishra, J., Stokowski, H. S., Mckenna, T. P., Langrock, C., Sudmeyer, T., Safavi-Naeini, A., Fejer, M. M. 2024; 11 (3): 315-325

  View details for DOI 10.1364/OPTICA.510591

  View details for Web of Science ID 001229255600001

• Single-mode squeezed-light generation and tomography with an integrated optical parametric oscillator. Science advances Park, T., Stokowski, H., Ansari, V., Gyger, S., Multani, K. K., Celik, O. T., Hwang, A. Y., Dean, D. J., Mayor, F., McKenna, T. P., Fejer, M. M., Safavi-Naeini, A. 2024; 10 (11): eadl1814

  Abstract

  Quantum optical technologies promise advances in sensing, computing, and communication. A key resource is squeezed light, where quantum noise is redistributed between optical quadratures. We introduce a monolithic, chip-scale platform that exploits the χ(2) nonlinearity of a thin-film lithium niobate (TFLN) resonator device to efficiently generate squeezed states of light. Our system integrates all essential components-except for the laser and two detectors-on a single chip with an area of one square centimeter, reducing the size, operational complexity, and power consumption associated with conventional setups. Using the balanced homodyne measurement subsystem that we implemented on the same chip, we measure a squeezing of 0.55 decibels and an anti-squeezing of 1.55 decibels. We use 20 milliwatts of input power to generate the parametric oscillator pump field by using second harmonic generation on the same chip. Our work represents a step toward compact and efficient quantum optical systems posed to leverage the rapid advances in integrated nonlinear and quantum photonics.

  View details for DOI 10.1126/sciadv.adl1814

  View details for PubMedID 38478618

• Integrated frequency-modulated optical parametric oscillator. Nature Stokowski, H. S., Dean, D. J., Hwang, A. Y., Park, T., Celik, O. T., McKenna, T. P., Jankowski, M., Langrock, C., Ansari, V., Fejer, M. M., Safavi-Naeini, A. H. 2024; 627 (8002): 95-100

  Abstract

  Optical frequency combs have revolutionized precision measurement, time-keeping and molecular spectroscopy1-7. A substantial effort has developed around 'microcombs': integrating comb-generating technologies into compact photonic platforms5,7-9. Current approaches for generating these microcombs involve either the electro-optic10 or Kerr mechanisms11. Despite rapid progress, maintaining high efficiency and wide bandwidth remains challenging. Here we introduce a previously unknown class of microcomb-an integrated device that combines electro-optics and parametric amplification to yield a frequency-modulated optical parametric oscillator (FM-OPO). In contrast to the other solutions, it does not form pulses but maintains operational simplicity and highly efficient pump power use with an output resembling a frequency-modulated laser12. We outline the working principles of our device and demonstrate it by fabricating the complete optical system in thin-film lithium niobate. We measure pump-to-comb internal conversion efficiency exceeding 93% (34% out-coupled) over a nearly flat-top spectral distribution spanning about 200 modes (over 1THz). Compared with an electro-optic comb, the cavity dispersion rather than loss determines the FM-OPO bandwidth, enabling broadband combs with a smaller radio-frequency modulation power. The FM-OPO microcomb offers robust operational dynamics, high efficiency and broad bandwidth, promising compact precision tools for metrology, spectroscopy, telecommunications, sensing and computing.

  View details for DOI 10.1038/s41586-024-07071-2

  View details for PubMedID 38448697

• Integrated frequency-modulated optical parametric oscillator NATURE Stokowski, H. S., Dean, D. J., Hwang, A. Y., Park, T., Celik, O., McKenna, T. P., Jankowski, M., Langrock, C., Ansari, V., Fejer, M. M., Safavi-Naeini, A. H. 2024; 627 (8002)

  View details for Web of Science ID 001171755900001

• Arbitrary electro-optic bandwidth and frequency control in lithium niobate optical resonators. Optics express Herrmann, J. F., Dean, D. J., Sarabalis, C. J., Ansari, V., Multani, K., Wollack, E. A., McKenna, T. P., Witmer, J. D., Safavi-Naeini, A. H. 2024; 32 (4): 6168-6177

  Abstract

  In situ tunable photonic filters and memories are important for emerging quantum and classical optics technologies. However, most photonic devices have fixed resonances and bandwidths determined at the time of fabrication. Here we present an in situ tunable optical resonator on thin-film lithium niobate. By leveraging the linear electro-optic effect, we demonstrate widely tunable control over resonator frequency and bandwidth on two different devices. We observe up to 50* tuning in the bandwidth over 50 V with linear frequency control of 230 MHz/V. We also develop a closed-form model predicting the tuning behavior of the device. This paves the way for rapid phase and amplitude control over light transmitted through our device.

  View details for DOI 10.1364/OE.502142

  View details for PubMedID 38439326

• Strong Dispersive Coupling Between a Mechanical Resonator and a Fluxonium Superconducting Qubit PRX QUANTUM Lee, N. A., Guo, Y., Cleland, A. Y., Wollack, E., Gruenke, R. G., Makihara, T., Wang, Z., Rajabzadeh, T., Jiang, W., Mayor, F. M., Arrangoiz-Arriola, P., Sarabalis, C. J., Safavi-Naeini, A. H. 2023; 4 (4)

  View details for DOI 10.1103/PRXQuantum.4.040342

  View details for Web of Science ID 001128802400001

• Efficient Photonic Integration of Diamond Color Centers and Thin-Film Lithium Niobate ACS PHOTONICS Riedel, D., Lee, H., Herrmann, J. F., Grzesik, J., Ansari, V., Borit, J., Stokowski, H. S., Aghaeimeibodi, S., Lu, H., McQuade, P. J., Melosh, N. A., Shen, Z., Safavi-Naeini, A. H., Vuckovic, J. 2023; 10 (12): 4236-4243

  View details for DOI 10.1021/acsphotonics.3c00992

  View details for Web of Science ID 001128748300001

• Mid-infrared spectroscopy with a broadly tunable thin-film lithium niobate optical parametric oscillator OPTICA Hwang, A., Stokowski, H. S., Park, T., Jankowski, M., Mckenna, T. P., Langrock, C., Mishra, J., Ansari, V., Fejer, M. M., Safavi-Naeini, A. H. 2023; 10 (11): 1535-1542

  View details for DOI 10.1364/OPTICA.502487

  View details for Web of Science ID 001111360700002

• Analysis of arbitrary superconducting quantum circuits accompanied by a Python package: SQcircuit QUANTUM Rajabzadeh, T., Wang, Z., Lee, N., Makihara, T., Guo, Y., Safavi-Naeini, A. H. 2023; 7

  View details for DOI 10.22331/q-2023-09-25-1118

  View details for Web of Science ID 001100940300001

• Flexible integration of gigahertz nanomechanical resonators with a superconducting microwave resonator using a bonded flip-chip method APPLIED PHYSICS LETTERS Malik, S., Jiang, W., Mayor, F. M., Makihara, T., Safavi-Naeini, A. H. 2023; 123 (10)

  View details for DOI 10.1063/5.0157516

  View details for Web of Science ID 001074765700009

• Identifying the Microscopic Nature of Two Level System Loss Channels in Acoustic Devices Using X-ray Photoelectron Spectroscopy and Atomic Force Microscopy. Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada Gruenke, R., Multani, G., Hitchcock, O., Wollack, E. A., Szakiel, E., Sarabalis, C., Lee, N., Cleland, A., Safavi-Naeini, A. 2023; 29 (Supplement_1): 776

  View details for DOI 10.1093/micmic/ozad067.384

  View details for PubMedID 37613561

• Optically heralded microwave photon addition NATURE PHYSICS Jiang, W., Mayor, F. M., Malik, S., Van Laer, R., McKenna, T. P., Patel, R. N., Witmer, J. D., Safavi-Naeini, A. H. 2023

  View details for DOI 10.1038/s41567-023-02129-w

  View details for Web of Science ID 001032623500004

• Integrated quantum optical phase sensor in thin film lithium niobate. Nature communications Stokowski, H. S., McKenna, T. P., Park, T., Hwang, A. Y., Dean, D. J., Celik, O. T., Ansari, V., Fejer, M. M., Safavi-Naeini, A. H. 2023; 14 (1): 3355

  Abstract

  The quantum noise of light, attributed to the random arrival time of photons from a coherent light source, fundamentally limits optical phase sensors. An engineered source of squeezed states suppresses this noise and allows phase detection sensitivity beyond the quantum noise limit (QNL). We need ways to use quantum light within deployable quantum sensors. Here we present a photonic integrated circuit in thin-film lithium niobate that meets these requirements. We use the second-order nonlinearity to produce a squeezed state at the same frequency as the pump light and realize circuit control and sensing with electro-optics. Using 26.2 milliwatts of optical power, we measure (2.7 ± 0.2)% squeezing and apply it to increase the signal-to-noise ratio of phase measurement. We anticipate that photonic systems like this, which operate with low power and integrate all of the needed functionality on a single die, will open new opportunities for quantum optical sensing.

  View details for DOI 10.1038/s41467-023-38246-6

  View details for PubMedID 37291141

  View details for PubMedCentralID 9352777

• Platform-agnostic waveguide integration of high-speed photodetectors with evaporated tellurium thin films OPTICA Ahn, G., White, A. D., Kim, H., Higashitarumizu, N., Mayor, F. M., Herrmann, J. F., Jiang, W., Multani, K. S., Safavi-Naeini, A. H., Javey, A., Vuckovic, J. 2023; 10 (3): 349-355

  View details for DOI 10.1364/OPTICA.475387

  View details for Web of Science ID 000983216600001

• Bias-stable Sub-Volt Visible Electro-optic Modulator in Thin-Film Lithium Niobate Celik, O., Ammar, N., Stokowski, H. S., Park, T., Safavi-Naeini, A., IEEE IEEE. 2023

  View details for DOI 10.1109/IPC57732.2023.10360599

  View details for Web of Science ID 001156890300101

• Tunable dual wavelength laser on thin film lithium niobate Lufungula, I., Mayor, F. M., Herrmann, J. F., Park, T., Stokowski, H. S., Hwang, A. Y., De Beeck, C., Atalar, O., Jiang, W., Kuyken, B., Safavi-Naeini, A. H., IEEE IEEE. 2023

  View details for DOI 10.1109/IPC57732.2023.10360651

  View details for Web of Science ID 001156890300147

• Y-Z cut lithium niobate longitudinal piezoelectric resonant photoelastic modulator OPTICS EXPRESS Atalar, O., Yee, S., Safavi-Naeini, A., Arbabian, A. 2022; 30 (26): 47103-47114

  Abstract

  The capability to modulate the intensity of an optical beam has scientific and practical significance. In this work, we demonstrate Y-Z cut lithium niobate acousto-optic modulators with record-high modulation efficiency, requiring only 1.5 W/cm2 for 100% modulation at 7 MHz. These modulators use a simple fabrication process; coating the top and bottom surfaces of a thin lithium niobate wafer with transparent electrodes. The fundamental shear acoustic mode of the wafer is excited through the transparent electrodes by applying voltage with frequency corresponding to the resonant frequency of this mode, confining an acoustic standing wave to the electrode region. Polarization of light propagating through this region is modulated at the applied frequency. Polarization modulation is converted to intensity modulation by placing the modulator between polarizers. To showcase an important application space for this modulator, we integrate it with a standard image sensor and demonstrate 4 megapixel time-of-flight imaging.

  View details for DOI 10.1364/OE.476970

  View details for Web of Science ID 000914755600002

  View details for PubMedID 36558647

• Integrated passive nonlinear optical isolators NATURE PHOTONICS White, A. D., Ahn, G., Gasse, K., Yang, K., Chang, L., Bowers, J. E., Vuckovic, J. 2022

  View details for DOI 10.1038/s41566-022-01110-y

  View details for Web of Science ID 000893052000001

• Ultra-broadband mid-infrared generation in dispersion-engineered thin-film lithium niobate OPTICS EXPRESS Mishra, J., Jankowski, M., Hwang, A. Y., Stokowski, H. S., McKenna, T. P., Langrock, C., Ng, E., Heydari, D., Mabuchi, H., Safavi-Naeini, A. H., Fejer, M. M. 2022; 30 (18): 32752-32760

  View details for DOI 10.1364/OE.467580

  View details for Web of Science ID 000850229100099

• Ultra-low-power second-order nonlinear optics on a chip. Nature communications McKenna, T. P., Stokowski, H. S., Ansari, V., Mishra, J., Jankowski, M., Sarabalis, C. J., Herrmann, J. F., Langrock, C., Fejer, M. M., Safavi-Naeini, A. H. 2022; 13 (1): 4532

  Abstract

  Second-order nonlinear optical processes convert light from one wavelength to another and generate quantum entanglement. Creating chip-scale devices to efficiently control these interactions greatly increases the reach of photonics. Existing silicon-based photonic circuits utilize the third-order optical nonlinearity, but an analogous integrated platform for second-order nonlinear optics remains an outstanding challenge. Here we demonstrate efficient frequency doubling and parametric oscillation with a threshold of tens of micro-watts in an integrated thin-film lithium niobate photonic circuit. We achieve degenerate and non-degenerate operation of the parametric oscillator at room temperature and tune its emission over one terahertz by varying the pump frequency by hundreds of megahertz. Finally, we observe cascaded second-order processes that result in parametric oscillation. These resonant second-order nonlinear circuits will form a crucial part of the emerging nonlinear and quantum photonics platforms.

  View details for DOI 10.1038/s41467-022-31134-5

  View details for PubMedID 35927246

• Mirror symmetric on-chip frequency circulation of light NATURE PHOTONICS Herrmann, J. F., Ansari, V., Wang, J., Witmer, J. D., Fan, S., Safavi-Naeini, A. H. 2022

  View details for DOI 10.1038/s41566-022-01026-7

  View details for Web of Science ID 000824862900001

• High-bandwidth CMOS-voltage-level electro-optic modulation of 780 nm light in thin-film lithium niobate OPTICS EXPRESS Celik, O., Sarabalis, C. J., Mayor, F. M., Stokowski, H. S., Herrmann, J. F., McKenna, T. P., Lee, N. A., Jiang, W., Multani, K. S., Safavi-Naeini, A. H. 2022; 30 (13): 23177-23186

  View details for DOI 10.1364/OE.460119

  View details for Web of Science ID 000813479600073

• High-efficiency second harmonic generation of blue light on thin-film lithium niobate. Optics letters Park, T., Stokowski, H. S., Ansari, V., McKenna, T. P., Hwang, A. Y., Fejer, M. M., Safavi-Naeini, A. H. 2022; 47 (11): 2706-2709

  Abstract

  The strength of interactions between photons in a chi(2) nonlinear optical waveguide increases at shorter wavelengths. These larger interactions enable coherent spectral translation and light generation at a lower power, over a broader bandwidth, and in a smaller device: all of which open the door to new technologies spanning fields from classical to quantum optics. Stronger interactions may also grant access to new regimes of quantum optics to be explored at the few-photon level. One promising platform that could enable these advances is thin-film lithium niobate (TFLN), due to its broad optical transparency window and possibility for quasi-phase matching and dispersion engineering. In this Letter, we demonstrate second harmonic generation of blue light on an integrated thin-film lithium niobate waveguide and observe a conversion efficiency of eta0=33, 000%/W-cm2, significantly exceeding previous demonstrations.

  View details for DOI 10.1364/OL.455046

  View details for PubMedID 35648910

• Automated Discovery of Autonomous Quantum Error Correction Schemes PRX QUANTUM Wang, Z., Rajabzadeh, T., Lee, N., Safavi-Naeini, A. H. 2022; 3 (2)

  View details for DOI 10.1103/PRXQuantum.3.020302

  View details for Web of Science ID 000784262100001

• Quantum state preparation and tomography of entangled mechanical resonators. Nature Wollack, E. A., Cleland, A. Y., Gruenke, R. G., Wang, Z., Arrangoiz-Arriola, P., Safavi-Naeini, A. H. 2022; 604 (7906): 463-467

  Abstract

  Precisely engineered mechanical oscillators keep time, filter signals and sense motion, making them an indispensable part of the technological landscape of today. These unique capabilities motivate bringing mechanical devices into the quantum domain by interfacing them with engineered quantum circuits. Proposals to combine microwave-frequency mechanical resonators with superconducting devices suggest the possibility of powerful quantum acoustic processors1-3. Meanwhile, experiments in several mechanical systems have demonstrated quantum state control and readout4,5, phonon number resolution6,7 and phonon-mediated qubit-qubit interactions8,9. At present, these acoustic platforms lack processors capable of controlling the quantum states of several mechanical oscillators with a single qubit and the rapid quantum non-demolition measurements of mechanical states needed for error correction. Here we use a superconducting qubit to control and read out the quantum state of a pair of nanomechanical resonators. Our device is capable of fast qubit-mechanics swap operations, which we use to deterministically manipulate the mechanical states. By placing the qubit into the strong dispersive regime with both mechanical resonators simultaneously, we determine the phonon number distributions of the resonators by means of Ramsey measurements. Finally, we present quantum tomography of the prepared nonclassical and entangled mechanical states. Our result represents a concrete step towards feedback-based operation of a quantum acoustic processor.

  View details for DOI 10.1038/s41586-022-04500-y

  View details for PubMedID 35444325

• Longitudinal piezoelectric resonant photoelastic modulator for efficient intensity modulation at megahertz frequencies. Nature communications Atalar, O., Van Laer, R., Safavi-Naeini, A. H., Arbabian, A. 2022; 13 (1): 1526

  Abstract

  Intensity modulators are an essential component in optics for controlling free-space beams. Many applications require the intensity of a free-space beam to be modulated at a single frequency, including wide-field lock-in detection for sensitive measurements, mode-locking in lasers, and phase-shift time-of-flight imaging (LiDAR). Here, we report a new type of single frequency intensity modulator that we refer to as a longitudinal piezoelectric resonant photoelastic modulator. The modulator consists of a thin lithium niobate wafer coated with transparent surface electrodes. One of the fundamental acoustic modes of the modulator is excited through the surface electrodes, confining an acoustic standing wave to the electrode region. The modulator is placed between optical polarizers; light propagating through the modulator and polarizers is intensity modulated with a wide acceptance angle and record breaking modulation efficiency in the megahertz frequency regime. As an illustration of the potential of our approach, we show that the proposed modulator can be integrated with a standard image sensor to effectively convert it into a time-of-flight imaging system.

  View details for DOI 10.1038/s41467-022-29204-9

  View details for PubMedID 35318321

• Building a Fault-Tolerant Quantum Computer Using Concatenated Cat Codes PRX QUANTUM Chamberland, C., Noh, K., Arrangoiz-Arriola, P., Campbell, E. T., Hann, C. T., Iverson, J., Putterman, H., Bohdanowicz, T. C., Flammia, S. T., Keller, A., Refael, G., Preskill, J., Jiang, L., Safavi-Naeini, A. H., Painter, O., Brandao, F. L. 2022; 3 (1)

  View details for DOI 10.1103/PRXQuantum.3.010329

  View details for Web of Science ID 000761410700001

• 2022 Roadmap on integrated quantum photonics JOURNAL OF PHYSICS-PHOTONICS Moody, G., Sorger, V. J., Blumenthal, D. J., Juodawlkis, P. W., Loh, W., Sorace-Agaskar, C., Jones, A. E., Balram, K. C., Matthews, J. F., Laing, A., Davanco, M., Chang, L., Bowers, J. E., Quack, N., Galland, C., Aharonovich, I., Wolff, M. A., Schuck, C., Sinclair, N., Loncar, M., Komljenovic, T., Weld, D., Mookherjea, S., Buckley, S., Radulaski, M., Reitzenstein, S., Pingault, B., Machielse, B., Mukhopadhyay, D., Akimov, A., Zheltikov, A., Agarwal, G. S., Srinivasan, K., Lu, J., Tang, H. X., Jiang, W., McKenna, T. P., Safavi-Naeini, A. H., Steinhauer, S., Elshaari, A. W., Zwiller, V., Davids, P. S., Martinez, N., Gehl, M., Chiaverini, J., Mehta, K. K., Romero, J., Lingaraju, N. B., Weiner, A. M., Peace, D., Cernansky, R., Lobino, M., Diamanti, E., Vidarte, L., Camacho, R. M. 2022; 4 (1)

  View details for DOI 10.1088/2515-7647/ac1ef4

  View details for Web of Science ID 000749511600001

• Superconducting on-chip tunable mm-wave resonator Das, D., Naji, A., Multani, K. S., Safavi-Naeini, A. H., Nanni, E. A., IEEE IEEE. 2022

  View details for DOI 10.1109/IRMMW-THz50927.2022.9895550

  View details for Web of Science ID 000865953000075

• III/V-on-lithium niobate amplifiers and lasers OPTICA de Beeck, C., Mayor, F. M., Cuyvers, S., Poelman, S., Herrmann, J. F., Atalar, O., McKenna, T. P., Haq, B., Jiang, W., Witmer, J. D., Roelkens, G., Safavi-Naeini, A. H., Van Laer, R., Kuyken, B. 2021; 8 (10): 1288-1289

  View details for DOI 10.1364/OPTICA.438620

  View details for Web of Science ID 000709553000008

• Control Design for Inhomogeneous-Broadening Compensation in Single-Photon PHYSICAL REVIEW APPLIED Mishra, S., Trivedi, R., Safavi-Naeini, A. H., Vuckovic, J. 2021; 16 (4)

  View details for DOI 10.1103/PhysRevApplied.16.044025

  View details for Web of Science ID 000708446800003

• Mid-infrared nonlinear optics in thin-film lithium niobate on sapphire OPTICA Mishra, J., McKenna, T. P., Ng, E., Stokowski, H. S., Jankowski, M., Langrock, C., Heydari, D., Mabuchi, H., Fejer, M. M., Safavi-Naeini, A. H. 2021; 8 (6): 921-924

  View details for DOI 10.1364/OPTICA.427428

  View details for Web of Science ID 000663363600024

• Number Partitioning With Grover's Algorithm in Central Spin Systems PRX QUANTUM Anikeeva, G., Markovic, O., Borish, V., Hines, J. A., Rajagopal, S., Cooper, E. S., Periwal, A., Safavi-Naeini, A., Davis, E. J., Schleier-Smith, M. 2021; 2 (2)

  View details for DOI 10.1103/PRXQuantum.2.020319

  View details for Web of Science ID 000674719600001

• Acousto-optic modulation of a wavelength-scale waveguide OPTICA Sarabalis, C. J., Van Laer, R., Patel, R. N., Dahmani, Y. D., Jiang, W., Mayor, F. M., Safavi-Naeini, A. H. 2021; 8 (4): 477-483

  View details for DOI 10.1364/OPTICA.413401

  View details for Web of Science ID 000642200300008

• Loss channels affecting lithium niobate phononic crystal resonators at cryogenic temperature APPLIED PHYSICS LETTERS Wollack, E., Cleland, A. Y., Arrangoiz-Arriola, P., McKenna, T. P., Gruenke, R. G., Patel, R. N., Jiang, W., Sarabalis, C. J., Safavi-Naeini, A. H. 2021; 118 (12)

  View details for DOI 10.1063/5.0034909

  View details for Web of Science ID 000632733300001

• Development of Quantum Interconnects (QuICs) for Next-Generation Information Technologies PRX QUANTUM Awschalom, D., Berggren, K. K., Bernien, H., Bhave, S., Carr, L. D., Davids, P., Economou, S. E., Englund, D., Faraon, A., Fejer, M., Guha, S., Gustafsson, M., Hu, E., Jiang, L., Kim, J., Korzh, B., Kumar, P., Kwiat, P. G., Loncar, M., Lukin, M. D., Miller, D. B., Monroe, C., Nam, S., Narang, P., Orcutt, J. S., Raymer, M. G., Safavi-Naeini, A. H., Spiropulu, M., Srinivasan, K., Sun, S., Vuckovic, J., Waks, E., Walsworth, R., Weiner, A. M., Zhang, Z. 2021; 2 (1)

  View details for DOI 10.1103/PRXQuantum.2.017002

  View details for Web of Science ID 000674685900002

• Gigahertz Phononic Integrated Circuits on Thin-Film Lithium Niobate on Sapphire PHYSICAL REVIEW APPLIED Mayor, F. M., Jiang, W., Sarabalis, C. J., McKenna, T. P., Witmer, J. D., Safavi-Naeini, A. H. 2021; 15 (1)

  View details for DOI 10.1103/PhysRevApplied.15.014039

  View details for Web of Science ID 000609266200003

• Fully-Resonant Second Harmonic Generation in Periodically Poled Thin-Film Lithium Niobate McKenna, T. P., Stokowski, H. S., Ansari, V., Mishra, J., Jankowski, M., Sarabalis, C. J., Herrmann, J. F., Langrock, C., Fejer, M. M., Safavi-Naeini, A. H., IEEE IEEE. 2021

  View details for Web of Science ID 000831479801219

• Room-Temperature Mechanical Resonator with a Single Added or Subtracted Phonon. Physical review letters Patel, R. N., McKenna, T. P., Wang, Z., Witmer, J. D., Jiang, W., Van Laer, R., Sarabalis, C. J., Safavi-Naeini, A. H. 2021; 127 (13): 133602

  Abstract

  A room-temperature mechanical oscillator undergoes thermal Brownian motion with an amplitude much larger than the amplitude associated with a single phonon of excitation. This motion can be read out and manipulated using laser light using a cavity-optomechanical approach. By performing a strong quantum measurement (i.e., counting single photons in the sidebands imparted on a laser), we herald the addition and subtraction of single phonons on the 300 K thermal motional state of a 4 GHz mechanical oscillator. To understand the resulting mechanical state, we implement a tomography scheme and observe highly non-Gaussian phase-space distributions. Using a maximum likelihood method, we infer the density matrix of the oscillator, and we confirm the counterintuitive doubling of the mean phonon number resulting from phonon addition and subtraction.

  View details for DOI 10.1103/PhysRevLett.127.133602

  View details for PubMedID 34623823

• Photonic Modal Circulator Using Temporal Refractive-Index Modulation with Spatial Inversion Symmetry. Physical review letters Wang, J., Herrmann, J. F., Witmer, J. D., Safavi-Naeini, A. H., Fan, S. 2021; 126 (19): 193901

  Abstract

  It has been demonstrated that dynamic refractive-index modulation, which breaks time-reversal symmetry, can be used to create on-chip nonreciprocal photonic devices. In order to achieve amplitude nonreciprocity, all such devices moreover require modulations that break spatial symmetries, which adds complexity in implementations. Here we introduce a modal circulator, which achieves amplitude nonreciprocity through a circulation motion among three modes. We show that such a circulator can be achieved in a dynamically modulated structure that preserves mirror symmetry, and as a result can be implemented using only a single standing-wave modulator, which significantly simplifies the implementation of dynamically modulated nonreciprocal devices. We also prove that in terms of the number of modes involved in the transport process, the modal circulator represents the minimum configuration in which complete amplitude nonreciprocity can be achieved while preserving spatial symmetry.

  View details for DOI 10.1103/PhysRevLett.126.193901

  View details for PubMedID 34047603

• Quantum Control of Microwave-to-Optical Transducers for Inhomogeneous Broadening Compensation Mishra, S., Trivedi, R., Safavi-Naeini, A. H., Vuckovic, J., IEEE IEEE. 2021

  View details for Web of Science ID 000831479800143

• Integrated thin-film lithium niobate non-reciprocal circulator Herrmann, J. F., Ansari, V., Wang, J., Witmer, J. D., Fan, S., Safavi-Naeini, A. H., IEEE IEEE. 2021

  View details for Web of Science ID 000831479801039

• Photonic modal circulator using dynamic modulation with mirror symmetry Wang, J., Herrmann, J., Witmer, J., Safavi-Naeini, A. H., Fan, S., IEEE IEEE. 2021

  View details for Web of Science ID 000831479801260

• Mid-infrared nonlinear optics in thin-film lithium niobate on sapphire Mishra, J., McKenna, T. P., Ng, E., Stokowski, H. S., Jankowski, M., Langrock, C., Heydari, D., Mabuchi, H., Safavi-Naeini, A. H., Fejer, M. M., IEEE IEEE. 2021

  View details for Web of Science ID 000831479802196

• Optical Parametric Oscillator in Thin-Film Lithium Niobate with a 130 mu W Threshold Stokowski, H. S., McKenna, T. P., Ansari, V., Mishra, J., Jankowski, M., Sarabalis, C. J., Herrmann, J. F., Langrock, C., Fejer, M. M., Safavi-Naeini, A. H., IEEE IEEE. 2021

  View details for Web of Science ID 000831479803278

• Cryogenic microwave-to-optical conversion using a triply resonant lithium-niobate-on-sapphire transducer OPTICA McKenna, T. P., Witmer, J. D., Patel, R. N., Jiang, W., Van Laer, R., Arrangoiz-Arriola, P., Wollack, E., Herrmann, J. F., Safavi-Naeini, A. H. 2020; 7 (12): 1737–45

  View details for DOI 10.1364/OPTICA.397235

  View details for Web of Science ID 000600773800014

• Nanobenders as efficient piezoelectric actuators for widely tunable nanophotonics at CMOS-level voltages COMMUNICATIONS PHYSICS Jiang, W., Mayor, F. M., Patel, R. N., McKenna, T. P., Sarabalis, C. J., Safavi-Naeini, A. H. 2020; 3 (1)

  View details for DOI 10.1038/s42005-020-00412-3

  View details for Web of Science ID 000565881800001

• Acousto-optic modulation in lithium niobate on sapphire APL PHOTONICS Sarabalis, C. J., McKenna, T. P., Patel, R. N., Van Laer, R., Safavi-Naeini, A. H. 2020; 5 (8)

  View details for DOI 10.1063/5.0012288

  View details for Web of Science ID 000562846100001

• A silicon-organic hybrid platform for quantum microwave-to-optical transduction QUANTUM SCIENCE AND TECHNOLOGY Witmer, J. D., McKenna, T. P., Arrangoiz-Arriola, P., Van Laer, R., Alex Wollack, E., Lin, F., Jen, A., Luo, J., Safavi-Naeini, A. H. 2020; 5 (3)

  View details for DOI 10.1088/2058-9565/ab7eed

  View details for Web of Science ID 000531294900001

• Piezoelectric Transduction of a Wavelength-Scale Mechanical Waveguide PHYSICAL REVIEW APPLIED Dahmani, Y. D., Sarabalis, C. J., Jiang, W., Mayor, F. M., Safavi-Naeini, A. H. 2020; 13 (2)

  View details for DOI 10.1103/PhysRevApplied.13.024069

  View details for Web of Science ID 000515710800005

• Time-of-flight imaging based on resonant photoelastic modulation (vol 58, pg 2235, 2019) APPLIED OPTICS Atalar, O., Van Laer, R., Sarabalis, C. J., Safavi-Naeini, A. H., Arbabian, A. 2020; 59 (5): 1430

  Abstract

  This publisher's note corrects the Funding section in Appl. Opt.58, 2235 (2019)APOPAI0003-693510.1364/AO.58.002235.

  View details for DOI 10.1364/AO.389202

  View details for Web of Science ID 000526522300059

  View details for PubMedID 32225397

• S-band delay lines in suspended lithium niobate JOURNAL OF APPLIED PHYSICS Sarabalis, C. J., Dahmani, Y. D., Cleland, A. Y., Safavi-Naeini, A. H. 2020; 127 (5)

  View details for DOI 10.1063/1.5126428

  View details for Web of Science ID 000513135300009

• Lithium Niobate Resonant Photoelastic Modulator for Time-of-Flight Imaging Atalar, O., Van Laer, R., Sarabalis, C. J., Safavi-Naeini, A. H., Arbabian, A., IEEE IEEE. 2020

  View details for Web of Science ID 000612090001179

• Development of a Millimeter-Wave Transducer for Quantum Networks Multani, K. S., Stokowski, H., Snively, E., Patel, R., Jiang, W., Lee, N., Welander, P. B., Nanni, E. A., Safavi-Naeini, A. H., IEEE IEEE. 2020

  View details for DOI 10.1109/IRMMW-THZ46771.2020.9370661

  View details for Web of Science ID 000662887600252

• Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency. Nature communications Jiang, W. n., Sarabalis, C. J., Dahmani, Y. D., Patel, R. N., Mayor, F. M., McKenna, T. P., Van Laer, R. n., Safavi-Naeini, A. H. 2020; 11 (1): 1166

  Abstract

  Efficient interconversion of both classical and quantum information between microwave and optical frequency is an important engineering challenge. The optomechanical approach with gigahertz-frequency mechanical devices has the potential to be extremely efficient due to the large optomechanical response of common materials, and the ability to localize mechanical energy into a micron-scale volume. However, existing demonstrations suffer from some combination of low optical quality factor, low electrical-to-mechanical transduction efficiency, and low optomechanical interaction rate. Here we demonstrate an on-chip piezo-optomechanical transducer that systematically addresses all these challenges to achieve nearly three orders of magnitude improvement in conversion efficiency over previous work. Our modulator demonstrates acousto-optic modulation with [Formula: see text] = 0.02 V. We show bidirectional conversion efficiency of [Formula: see text] with 3.3 μW  red-detuned optical pump, and [Formula: see text] with 323 μW blue-detuned pump. Further study of quantum transduction at millikelvin temperatures is required to understand how the efficiency and added noise are affected by reduced mechanical dissipation, thermal conductivity, and thermal capacity.

  View details for DOI 10.1038/s41467-020-14863-3

  View details for PubMedID 32127538

• Photonics-to-Free-Space Interface in Lithium Niobate-on-Sapphire Rajabzadeh, T., Sarabalis, C. J., Atalar, O., Safavi-Naeini, A. H., IEEE IEEE. 2020

  View details for Web of Science ID 000612090001404

• Acousto-Optics in Lithium Niobate-on-Sapphire Sarabalis, C. J., McKenna, T. P., Patel, R. N., Safavi-Naeini, A. H., IEEE IEEE. 2020

  View details for Web of Science ID 000612090001353

• Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency Jiang, W., Sarabalis, C. J., Dahmani, Y. D., Patel, R. N., Mayor, F. M., McKenna, T. P., Van Laer, R., Safavi-Naeini, A. H., IEEE IEEE. 2020

  View details for Web of Science ID 000612090001229

• Nanobenders: efficient piezoelectric actuators for widely tunable nanophotonics at CMOS-level voltages Jiang, W., Mayor, F. M., Patel, R. N., McKenna, T. P., Sarabalis, C. J., Safavi-Naeini, A. H., IEEE IEEE. 2020

  View details for Web of Science ID 000612090001483

• Piezo-optomechanics in lithium niobate on silicon-on-insulator for microwave-to-optics transduction Van Laer, R., Jiang, W., Patel, R. N., Sarabalis, C. J., Cleland, A., McKenna, T. P., Wollack, E., Witmer, J. D., Safavi-Naeini, A. H., IEEE IEEE. 2020

  View details for Web of Science ID 000612090002012

• Mechanical Purcell filters for microwave quantum machines APPLIED PHYSICS LETTERS Cleland, A. Y., Pechal, M., Stas, P. C., Sarabalis, C. J., Wollack, E., Safavi-Naeini, A. H. 2019; 115 (26)

  View details for DOI 10.1063/1.5111151

  View details for Web of Science ID 000505613600017

• Cryogenic packaging of an optomechanical crystal OPTICS EXPRESS McKenna, T. P., Patel, R. N., Witmer, J. D., Van Laer, R., Valery, J. A., Safavi-Naeini, A. H. 2019; 27 (20): 28782–91

  View details for DOI 10.1364/OE.27.028782

  View details for Web of Science ID 000488282800134

• Lithium niobate piezo-optomechanical crystals OPTICA Jiang, W., Patel, R. N., Mayor, F. M., Mckenna, T. P., Arrangoiz-Arriola, P., Sarabalis, C. J., Witmer, J. D., Van Laer, R., Safavi-Naeini, A. H. 2019; 6 (7): 845–53

  View details for DOI 10.1364/OPTICA.6.000845

  View details for Web of Science ID 000476637300003

• Resolving the energy levels of a nanomechanical oscillator. Nature Arrangoiz-Arriola, P., Wollack, E. A., Wang, Z., Pechal, M., Jiang, W., McKenna, T. P., Witmer, J. D., Van Laer, R., Safavi-Naeini, A. H. 2019; 571 (7766): 537–40

  Abstract

  The quantum nature of an oscillating mechanical object is anything but apparent. The coherent states that describe the classical motion of a mechanical oscillator do not have a well defined energy, but are quantum superpositions of equally spaced energy eigenstates. Revealing this quantized structure is only possible with an apparatus that measures energy with a precision greater than the energy of a single phonon. One way to achieve this sensitivity is by engineering a strong but nonresonant interaction between the oscillator and an atom. In a system with sufficient quantum coherence, this interaction allows one to distinguish different energy eigenstates using resolvable differences in the atom's transition frequency. For photons, such dispersive measurements have been performed in cavity1,2 and circuit quantum electrodynamics3. Here we report an experiment in which an artificial atom senses the motional energy of a driven nanomechanical oscillator with sufficient sensitivity to resolve the quantization of its energy. To realize this, we build a hybrid platform that integrates nanomechanical piezoelectric resonators with a microwave superconducting qubit on the same chip. We excite phonons with resonant pulses and probe the resulting excitation spectrum of the qubit to observe phonon-number-dependent frequency shifts that are about five times larger than the qubit linewidth. Our result demonstrates a fully integrated platform for quantum acoustics that combines large couplings, considerable coherence times and excellent control over the mechanical mode structure. With modest experimental improvements, we expect that our approach will enable quantum nondemolition measurements of phonons4 and will lead to quantum sensors and information-processing approaches5 that use chip-scale nanomechanical devices.

  View details for DOI 10.1038/s41586-019-1386-x

  View details for PubMedID 31341303

• Quantum Dynamics of a Few-Photon Parametric Oscillator PHYSICAL REVIEW X Wang, Z., Pechal, M., Wollack, E., Arrangoiz-Arriola, P., Gao, M., Lee, N. R., Safavi-Naeini, A. H. 2019; 9 (2)

  View details for DOI 10.1103/PhysRevX.9.021049

  View details for Web of Science ID 000470879100001

• Controlling phonons and photons at the wavelength scale: integrated photonics meets integrated phononics (vol 6, pg 213, 2019) OPTICA Safavi-Naeini, A. H., Van Thourhout, D., Baets, R., Van Laer, R. 2019; 6 (4): 410

  View details for DOI 10.1364/OPTICA.6.000410

  View details for Web of Science ID 000465296100006

• Diamond optomechanical crystals with embedded nitrogen-vacancy centers QUANTUM SCIENCE AND TECHNOLOGY Cady, J., Michel, O., Lee, K. W., Patel, R. N., Sarabalis, C. J., Safavi-Naeini, A. H., Jayich, A. 2019; 4 (2)

  View details for DOI 10.1088/2058-9565/ab043e

  View details for Web of Science ID 000460461900004

• Time-of-flight imaging based on resonant photoelastic modulation APPLIED OPTICS Atalar, O., Van Laer, R., Sarabalis, C. J., Safavi-Naeini, A. H., Arbabian, A. 2019; 58 (9): 2235–47

  View details for DOI 10.1364/AO.58.002235

  View details for Web of Science ID 000461903600013

• Controlling phonons and photons at the wavelength scale: integrated photonics meets integrated phononics OPTICA Safavi-Naeini, A. H., Van Thourhout, D., Baets, R., Van Laer, R. 2019; 6 (2): 213–32

  View details for DOI 10.1364/OPTICA.6.000213

  View details for Web of Science ID 000459192000018

• Superconducting circuit quantum computing with nanomechanical resonators as storage QUANTUM SCIENCE AND TECHNOLOGY Pechal, M., Arrangoiz-Arriola, P., Safavi-Naeini, A. H. 2019; 4 (1)

  View details for DOI 10.1088/2058-9565/aadc6c

  View details for Web of Science ID 000444911800001

• Electro-Optics with Gigahertz Phonons in Silicon Photonics Van Laer, R., Patel, R. N., Witmer, J. D., McKenna, T. P., Safavi-Naeini, A. H., IEEE IEEE. 2019

  View details for Web of Science ID 000482226301003

• High-quality Lithium Niobate Optomechanical Crystal Jiang, W., Patel, R. N., Mayor, F. M., McKenna, T. P., Arrangoiz-Arriola, P., Sarabalis, C. J., Van Laer, R., Safavi-Naeini, A. H., IEEE IEEE. 2019

  View details for Web of Science ID 000482226300036

• Quantum Acoustics with Lithium Niobate Nanocavities Arrangoiz-Arriola, P., Wollack, E., Pechal, M., Jiang, W., Wang, Z., McKenna, T. P., Safavi-Naeini, A. H., IEEE IEEE. 2019

  View details for Web of Science ID 000482226300008

• Frequency Tunable Single-Photon Emission From a Single Atomic Defect in a Solid Sun, S., Zhang, J., Fischer, K. A., Burek, M. J., Dory, C., Lagoudakis, K. G., Tzeng, Y., Radulaski, M., Kelaita, Y., Safavi-Naeini, A., Shen, Z., Melosh, N. A., Chu, S., Loncar, M., Vuckovic, J., IEEE IEEE. 2019

  View details for Web of Science ID 000482226303114

• Microwave Quantum Acoustic Processor Arrangoiz-Arriola, P., Wollack, E., Pechal, M., Jiang, W., Wang, Z., McKenna, T. P., Witmer, J., Van Laer, R., Cleland, A., Lee, N., Sarabalis, C. J., Stas, P., Safavi-Naeini, A. H., IEEE IEEE. 2019: 255–58

  View details for Web of Science ID 000494461700066

• Painting Nonclassical States of Spin or Motion with Shaped Single Photons. Physical review letters Davis, E. J., Wang, Z., Safavi-Naeini, A. H., Schleier-Smith, M. H. 2018; 121 (12): 123602

  Abstract

  We propose a robust scheme for generating macroscopic superposition states of spin or motion with the aid of a single photon. Shaping the wave packet of the photon enables high-fidelity preparation of nonclassical states of matter even in the presence of photon loss. Success is heralded by photodetection, enabling the scheme to be implemented with a weak coherent field. We analyze applications to preparing Schrödinger cat states of a collective atomic spin or of a mechanical oscillator coupled to an optical resonator. The method generalizes to preparing arbitrary superpositions of coherent states, enabling full quantum control. We illustrate this versatility by showing how to prepare Dicke or Fock states, as well as superpositions in the Dicke or Fock basis.

  View details for DOI 10.1103/PhysRevLett.121.123602

  View details for PubMedID 30296158

• Painting Nonclassical States of Spin or Motion with Shaped Single Photons PHYSICAL REVIEW LETTERS Davis, E. J., Wang, Z., Safavi-Naeini, A. H., Schleier-Smith, M. H. 2018; 121 (12)

  View details for DOI 10.1103/PhysRevLett.121.123602

  View details for Web of Science ID 000444961000001

• Cavity-Enhanced Raman Emission from a Single Color Center in a Solid. Physical review letters Sun, S., Zhang, J. L., Fischer, K. A., Burek, M. J., Dory, C., Lagoudakis, K. G., Tzeng, Y., Radulaski, M., Kelaita, Y., Safavi-Naeini, A., Shen, Z., Melosh, N. A., Chu, S., Loncar, M., Vuckovic, J. 2018; 121 (8): 083601

  Abstract

  We demonstrate cavity-enhanced Raman emission from a single atomic defect in a solid. Our platform is a single silicon-vacancy center in diamond coupled with a monolithic diamond photonic crystal cavity. The cavity enables an unprecedented frequency tuning range of the Raman emission (100GHz) that significantly exceeds the spectral inhomogeneity of silicon-vacancy centers in diamond nanostructures. We also show that the cavity selectively suppresses the phonon-induced spontaneous emission that degrades the efficiency of Raman photon generation. Our results pave the way towards photon-mediated many-body interactions between solid-state quantum emitters in a nanophotonic platform.

  View details for PubMedID 30192607

• Optomechanical antennas for on-chip beam-steering OPTICS EXPRESS Sarabalis, C. J., Van Laer, R., Safavi-Naeini, A. H. 2018; 26 (17): 22075–99

  Abstract

  Rapid and low-power control over the direction of a radiating light field is a major challenge in photonics and a key enabling technology for emerging sensors and free-space communication links. Current approaches based on bulky motorized components are limited by their high cost and power consumption, while on-chip optical phased arrays face challenges in scaling and programmability. Here, we propose a solid-state approach to beam-steering using optomechanical antennas. We combine recent progress in simultaneous control of optical and mechanical waves with remarkable advances in on-chip optical phased arrays to enable low-power and full two-dimensional beam-steering of monochromatic light. We present a design of a silicon photonic system made of photonic-phononic waveguides that achieves 44° field of view with 880 resolvable spots by sweeping the mechanical wavelength with about a milliwatt of mechanical power. Using mechanical waves as nonreciprocal, active gratings allows us to quickly reconfigure the beam direction, beam shape, and the number of beams. It also enables us to distinguish between light that we send and receive.

  View details for DOI 10.1364/OE.26.022075

  View details for Web of Science ID 000442136200061

  View details for PubMedID 30130907

• Single-Mode Phononic Wire. Physical review letters Patel, R. N., Wang, Z., Jiang, W., Sarabalis, C. J., Hill, J. T., Safavi-Naeini, A. H. 2018; 121 (4): 040501

  Abstract

  Photons and electrons transmit information to form complex systems and networks. Phonons on the other hand, the quanta of mechanical motion, are often considered only as carriers of thermal energy. Nonetheless, their flow can also be molded in fabricated nanoscale circuits. We design and experimentally demonstrate wires for phonons by patterning the surface of a silicon chip. Our device eliminates all but one channel of phonon conduction, allowing coherent phonon transport over millimeter length scales. We characterize the phononic wire optically, by coupling it strongly to an optomechanical transducer. The phononic wire enables new ways to manipulate information and energy on a chip. In particular, our result is an important step towards realizing on-chip phonon networks, in which quantum information is transmitted between nodes via phonons.

  View details for DOI 10.1103/PhysRevLett.121.040501

  View details for PubMedID 30095955

• Single-Mode Phononic Wire PHYSICAL REVIEW LETTERS Patel, R. N., Wang, Z., Jiang, W., Sarabalis, C. J., Hill, J. T., Safavi-Naeini, A. H. 2018; 121 (4)

  View details for DOI 10.1103/PhysRevLett.121.040501

  View details for Web of Science ID 000439547100002

• Coupling a Superconducting Quantum Circuit to a Phononic Crystal Defect Cavity PHYSICAL REVIEW X Arrangoiz-Arriola, P., Wollack, E., Pechal, M., Witmer, J. D., Hill, J. T., Safavi-Naeini, A. H. 2018; 8 (3)

  View details for DOI 10.1103/PhysRevX.8.031007

  View details for Web of Science ID 000438041400001

• Enhancing a slow and weak optomechanical nonlinearity with delayed quantum feedback NATURE COMMUNICATIONS Wang, Z., Safavi-Naeini, A. H. 2017; 8: 15886

  Abstract

  A central goal of quantum optics is to generate large interactions between single photons so that one photon can strongly modify the state of another one. In cavity optomechanics, photons interact with the motional degrees of freedom of an optical resonator, for example, by imparting radiation pressure forces on a movable mirror or sensing minute fluctuations in the position of the mirror. Here, we show that the optical nonlinearity arising from these effects, typically too small to operate on single photons, can be sufficiently enhanced with feedback to generate large interactions between single photons. We propose a protocol that allows photons propagating in a waveguide to interact with each other through multiple bounces off an optomechanical system. The protocol is analysed by evolving the full many-body quantum state of the waveguide-coupled system, illustrating that large photon-photon interactions mediated by mechanical motion may be within experimental reach.

  View details for PubMedID 28677674

• High-Q photonic resonators and electro-optic coupling using silicon-on-lithium-niobate SCIENTIFIC REPORTS Witmer, J. D., Valery, J. A., Arrangoiz-Arriola, P., Sarabalis, C. J., Hill, J. T., Safavi-Naeini, A. H. 2017; 7

  Abstract

  Future quantum networks, in which superconducting quantum processors are connected via optical links, will require microwave-to-optical photon converters that preserve entanglement. A doubly-resonant electro-optic modulator (EOM) is a promising platform to realize this conversion. Here, we present our progress towards building such a modulator by demonstrating the optically-resonant half of the device. We demonstrate high quality (Q) factor ring, disk and photonic crystal resonators using a hybrid silicon-on-lithium-niobate material system. Optical Q factors up to 730,000 are achieved, corresponding to propagation loss of 0.8 dB/cm. We also use the electro-optic effect to modulate the resonance frequency of a photonic crystal cavity, achieving a electro-optic modulation coefficient between 1 and 2 pm/V. In addition to quantum technology, we expect that our results will be useful both in traditional silicon photonics applications and in high-sensitivity acousto-optic devices.

  View details for DOI 10.1038/srep46313

  View details for Web of Science ID 000399157100001

  View details for PubMedID 28406177

• Thermal Brillouin noise observed in silicon optomechanical waveguide JOURNAL OF OPTICS Van Laer, R., Sarabalis, C. J., Baets, R., Van Thourhout, D., Safavi-Naeini, A. H. 2017; 19 (4)

  View details for DOI 10.1088/2040-8986/aa600d

  View details for Web of Science ID 000397617300001

• Enabling Strong Coupling in Nanoscale Silicon Optomechanical Waveguides Van Laer, R., Safavi-Naeini, A., IEEE IEEE. 2017

  View details for Web of Science ID 000427296200237

• Engineering interactions between superconducting qubits and phononic nanostructures PHYSICAL REVIEW A Arrangoiz-Arriola, P., Safavi-Naeini, A. H. 2016; 94 (6)

  View details for DOI 10.1103/PhysRevA.94.063864

  View details for Web of Science ID 000390962900011

• Design of nanobeam photonic crystal resonators for a silicon-on-lithium-niobate platform OPTICS EXPRESS Witmer, J. D., Hill, J. T., Safavi-Naeini, A. H. 2016; 24 (6): 5876-5885

  Abstract

  We outline the design for a photonic crystal resonator made in a hybrid Silicon/Lithium Niobate material system. Using the index contrast between silicon and lithium niobate, it is possible to guide and confine photonic resonances in a thin film of silicon bonded on top of lithium niobate. Quality factors greater than 10⁶ at optical wavelength scale mode volumes are achievable. We show that patterning electrodes on such a system can yield an electro-optic coupling rate of 0.6 GHz/V (4 pm/V).

  View details for DOI 10.1364/OE.24.005876

  View details for Web of Science ID 000373395700046

  View details for PubMedID 27136784

• Nonlinear Radiation Pressure Dynamics in an Optomechanical Crystal PHYSICAL REVIEW LETTERS Krause, A. G., Hill, J. T., Ludwig, M., Safavi-Naeini, A. H., Chan, J., Marquardt, F., Painter, O. 2015; 115 (23)

  View details for DOI 10.1103/PhysRevLett.115.233601

  View details for PubMedID 26684117

• Phonon counting and intensity interferometry of a nanomechanical resonator NATURE Cohen, J. D., Meenehan, S. M., MacCabe, G. S., Groeblacher, S., Safavi-Naeini, A. H., Marsili, F., Shaw, M. D., Painter, O. 2015; 520 (7548): 522-525

  Abstract

  In optics, the ability to measure individual quanta of light (photons) enables a great many applications, ranging from dynamic imaging within living organisms to secure quantum communication. Pioneering photon counting experiments, such as the intensity interferometry performed by Hanbury Brown and Twiss to measure the angular width of visible stars, have played a critical role in our understanding of the full quantum nature of light. As with matter at the atomic scale, the laws of quantum mechanics also govern the properties of macroscopic mechanical objects, providing fundamental quantum limits to the sensitivity of mechanical sensors and transducers. Current research in cavity optomechanics seeks to use light to explore the quantum properties of mechanical systems ranging in size from kilogram-mass mirrors to nanoscale membranes, as well as to develop technologies for precision sensing and quantum information processing. Here we use an optical probe and single-photon detection to study the acoustic emission and absorption processes in a silicon nanomechanical resonator, and perform a measurement similar to that used by Hanbury Brown and Twiss to measure correlations in the emitted phonons as the resonator undergoes a parametric instability formally equivalent to that of a laser. Owing to the cavity-enhanced coupling of light with mechanical motion, this effective phonon counting technique has a noise equivalent phonon sensitivity of 0.89 ± 0.05. With straightforward improvements to this method, a variety of quantum state engineering tasks using mesoscopic mechanical resonators would be enabled, including the generation and heralding of single-phonon Fock states and the quantum entanglement of remote mechanical elements.

  View details for DOI 10.1038/nature14349

  View details for Web of Science ID 000353334500038

  View details for PubMedID 25903632

• Strong opto-electro-mechanical coupling in a silicon photonic crystal cavity OPTICS EXPRESS Pitanti, A., Fink, J. M., Safavi-Naeini, A. H., Hill, J. T., Lei, C. U., Tredicucci, A., Painter, O. 2015; 23 (3): 3196-3208

  View details for DOI 10.1364/OE.23.003196

  View details for Web of Science ID 000349688800136

• Silicon optomechanical crystal resonator at millikelvin temperatures PHYSICAL REVIEW A Meenehan, S. M., Cohen, J. D., Groeblacher, S., Hill, J. T., Safavi-Naeini, A. H., Aspelmeyer, M., Painter, O. 2014; 90 (1)

  View details for DOI 10.1103/PhysRevA.90.011803

  View details for Web of Science ID 000339064100001

• Two-Dimensional Phononic-Photonic Band Gap Optomechanical Crystal Cavity PHYSICAL REVIEW LETTERS Safavi-Naeini, A. H., Hill, J. T., Meenehan, S., Chan, J., Groeblacher, S., Painter, O. 2014; 112 (15)

  View details for DOI 10.1103/PhysRevLett.112.153603

  View details for Web of Science ID 000337352600010

• Highly efficient coupling from an optical fiber to a nanoscale silicon optomechanical cavity APPLIED PHYSICS LETTERS Groeblacher, S., Hill, J. T., Safavi-Naeini, A. H., Chan, J., Painter, O. 2013; 103 (18)

  View details for DOI 10.1063/1.4826924

  View details for Web of Science ID 000327816000024

• Squeezed light from a silicon micromechanical resonator NATURE Safavi-Naeini, A. H., Groeblacher, S., Hill, J. T., Chan, J., Aspelmeyer, M., Painter, O. 2013; 500 (7461): 185-189

  Abstract

  Monitoring a mechanical object's motion, even with the gentle touch of light, fundamentally alters its dynamics. The experimental manifestation of this basic principle of quantum mechanics, its link to the quantum nature of light and the extension of quantum measurement to the macroscopic realm have all received extensive attention over the past half-century. The use of squeezed light, with quantum fluctuations below that of the vacuum field, was proposed nearly three decades ago as a means of reducing the optical read-out noise in precision force measurements. Conversely, it has also been proposed that a continuous measurement of a mirror's position with light may itself give rise to squeezed light. Such squeezed-light generation has recently been demonstrated in a system of ultracold gas-phase atoms whose centre-of-mass motion is analogous to the motion of a mirror. Here we describe the continuous position measurement of a solid-state, optomechanical system fabricated from a silicon microchip and comprising a micromechanical resonator coupled to a nanophotonic cavity. Laser light sent into the cavity is used to measure the fluctuations in the position of the mechanical resonator at a measurement rate comparable to its resonance frequency and greater than its thermal decoherence rate. Despite the mechanical resonator's highly excited thermal state (10(4) phonons), we observe, through homodyne detection, squeezing of the reflected light's fluctuation spectrum at a level 4.5 ± 0.2 per cent below that of vacuum noise over a bandwidth of a few megahertz around the mechanical resonance frequency of 28 megahertz. With further device improvements, on-chip squeezing at significant levels should be possible, making such integrated microscale devices well suited for precision metrology applications.

  View details for DOI 10.1038/nature12307

  View details for Web of Science ID 000322825500030

  View details for PubMedID 23925241

• Laser noise in cavity-optomechanical cooling and thermometry NEW JOURNAL OF PHYSICS Safavi-Naeini, A. H., Chan, J., Hill, J. T., Groeblacher, S., Miao, H., Chen, Y., Aspelmeyer, M., Painter, O. 2013; 15

  View details for DOI 10.1088/1367-2630/15/3/035007

  View details for Web of Science ID 000316187000003

• Si3N4 nanobeam optomechanical crystals 2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) Davanco, M., Chan, J., Safavi-Naeini, A. H., Painter, O., Srinivasan, K. 2013

  View details for Web of Science ID 000355262503171

• Coherent optical wavelength conversion via cavity optomechanics NATURE COMMUNICATIONS Hill, J. T., Safavi-Naeini, A. H., Chan, J., Painter, O. 2012; 3

  Abstract

  Both classical and quantum systems utilize the interaction of light and matter across a wide range of energies. These systems are often not naturally compatible with one another and require a means of converting photons of dissimilar wavelengths to combine and exploit their different strengths. Here we theoretically propose and experimentally demonstrate coherent wavelength conversion of optical photons using photon-phonon translation in a cavity-optomechanical system. For an engineered silicon optomechanical crystal nanocavity supporting a 4-GHz localized phonon mode, optical signals in a 1.5 MHz bandwidth are coherently converted over a 11.2 THz frequency span between one cavity mode at wavelength 1,460 nm and a second cavity mode at 1,545 nm with a 93% internal (2% external) peak efficiency. The thermal- and quantum-limiting noise involved in the conversion process is also analysed, and in terms of an equivalent photon number signal level are found to correspond to an internal noise level of only 6 and 4 × 10(-3) quanta, respectively.

  View details for DOI 10.1038/ncomms2201

  View details for Web of Science ID 000315992100031

  View details for PubMedID 23149741

• Slot-mode-coupled optomechanical crystals OPTICS EXPRESS Davanco, M., Chan, J., Safavi-Naeini, A. H., Painter, O., Srinivasan, K. 2012; 20 (22): 24394-24410

  Abstract

  We present a design methodology and analysis of a cavity optomechanical system in which a localized GHz frequency mechanical mode of a nanobeam resonator is evanescently coupled to a high quality factor (Q > 10(6)) optical mode of a separate nanobeam optical cavity. Using separate nanobeams provides flexibility, enabling the independent design and optimization of the optics and mechanics of the system. In addition, the small gap (≈ 25 nm) between the two resonators gives rise to a slot mode effect that enables a large zero-point optomechanical coupling strength to be achieved, with g/2 π > 300 kHz in a Si(3)N(4) system at 980 nm and g/2 π ≈ 900 kHz in a Si system at 1550 nm. The fact that large coupling strengths to GHz mechanical oscillators can be achieved in Si(3)N(4) is important, as this material has a broad optical transparency window, which allows operation throughout the visible and near-infrared. As an application of this platform, we consider wide-band optical frequency conversion between 1300 nm and 980 nm, using two optical nanobeam cavities coupled on either side to the breathing mode of a mechanical nanobeam resonator.

  View details for DOI 10.1364/OE.20.024394

  View details for Web of Science ID 000310443400032

  View details for PubMedID 23187203

• Quantum back-action in measurements of zero-point mechanical oscillations PHYSICAL REVIEW A Khalili, F. Y., Miao, H., Yang, H., Safavi-Naeini, A. H., Painter, O., Chen, Y. 2012; 86 (3)

  View details for DOI 10.1103/PhysRevA.86.033840

  View details for Web of Science ID 000309102300013

• Optimized optomechanical crystal cavity with acoustic radiation shield APPLIED PHYSICS LETTERS Chan, J., Safavi-Naeini, A. H., Hill, J. T., Meenehan, S., Painter, O. 2012; 101 (8)

  View details for DOI 10.1063/1.4747726

  View details for Web of Science ID 000308420800015

• Enhanced Quantum Nonlinearities in a Two-Mode Optomechanical System PHYSICAL REVIEW LETTERS Ludwig, M., Safavi-Naeini, A. H., Painter, O., Marquardt, F. 2012; 109 (6)

  Abstract

  In cavity optomechanics, nanomechanical motion couples to a localized optical mode. The regime of single-photon strong coupling is reached when the optical shift induced by a single phonon becomes comparable to the cavity linewidth. We consider a setup in this regime comprising two optical modes and one mechanical mode. For mechanical frequencies nearly resonant to the optical level splitting, we find the photon-phonon and the photon-photon interactions to be significantly enhanced. In addition to dispersive phonon detection in a novel regime, this offers the prospect of optomechanical photon measurement. We study these quantum nondemolition detection processes using both analytical and numerical approaches.

  View details for DOI 10.1103/PhysRevLett.109.063601

  View details for Web of Science ID 000307283300005

  View details for PubMedID 23006265

• Observation of Quantum Motion of a Nanomechanical Resonator PHYSICAL REVIEW LETTERS Safavi-Naeini, A. H., Chan, J., Hill, J. T., Alegre, T. P., Krause, A., Painter, O. 2012; 108 (3)

  Abstract

  In this Letter we use resolved sideband laser cooling to cool a mesoscopic mechanical resonator to near its quantum ground state (phonon occupancy 2.6±0.2), and observe the motional sidebands generated on a second probe laser. Asymmetry in the sideband amplitudes provides a direct measure of the displacement noise power associated with quantum zero-point fluctuations of the nanomechanical resonator, and allows for an intrinsic calibration of the phonon occupation number.

  View details for DOI 10.1103/PhysRevLett.108.033602

  View details for Web of Science ID 000299328100002

  View details for PubMedID 22400740

• A chip-scale integrated cavity-electro-optomechanics platform OPTICS EXPRESS Winger, M., Blasius, T. D., Alegre, T. P., Safavi-Naeini, A. H., Meenehan, S., Cohen, J., Stobbe, S., Painter, O. 2011; 19 (25): 24905-24921

  Abstract

  We present an integrated optomechanical and electromechanical nanocavity, in which a common mechanical degree of freedom is coupled to an ultrahigh-Q photonic crystal defect cavity and an electrical circuit. The system allows for wide-range, fast electrical tuning of the optical nanocavity resonances, and for electrical control of optical radiation pressure back-action effects such as mechanical amplification (phonon lasing), cooling, and stiffening. These sort of integrated devices offer a new means to efficiently interconvert weak microwave and optical signals, and are expected to pave the way for a new class of micro-sensors utilizing optomechanical back-action for thermal noise reduction and low-noise optical read-out.

  View details for DOI 10.1364/OE.19.024905

  View details for Web of Science ID 000297702400008

  View details for PubMedID 22273884

• Laser cooling of a nanomechanical oscillator into its quantum ground state. Nature Chan, J., Alegre, T. P., Safavi-Naeini, A. H., Hill, J. T., Krause, A., Gröblacher, S., Aspelmeyer, M., Painter, O. 2011; 478 (7367): 89-92

  Abstract

  The simple mechanical oscillator, canonically consisting of a coupled mass-spring system, is used in a wide variety of sensitive measurements, including the detection of weak forces and small masses. On the one hand, a classical oscillator has a well-defined amplitude of motion; a quantum oscillator, on the other hand, has a lowest-energy state, or ground state, with a finite-amplitude uncertainty corresponding to zero-point motion. On the macroscopic scale of our everyday experience, owing to interactions with its highly fluctuating thermal environment a mechanical oscillator is filled with many energy quanta and its quantum nature is all but hidden. Recently, in experiments performed at temperatures of a few hundredths of a kelvin, engineered nanomechanical resonators coupled to electrical circuits have been measured to be oscillating in their quantum ground state. These experiments, in addition to providing a glimpse into the underlying quantum behaviour of mesoscopic systems consisting of billions of atoms, represent the initial steps towards the use of mechanical devices as tools for quantum metrology or as a means of coupling hybrid quantum systems. Here we report the development of a coupled, nanoscale optical and mechanical resonator formed in a silicon microchip, in which radiation pressure from a laser is used to cool the mechanical motion down to its quantum ground state (reaching an average phonon occupancy number of 0.85 ± 0.08). This cooling is realized at an environmental temperature of 20 K, roughly one thousand times larger than in previous experiments and paves the way for optical control of mesoscale mechanical oscillators in the quantum regime.

  View details for DOI 10.1038/nature10461

  View details for PubMedID 21979049

• Laser cooling of a nanomechanical oscillator into its quantum ground state NATURE Chan, J., Mayer Alegre, T. P., Safavi-Naeini, A. H., Hill, J. T., Krause, A., Groeblacher, S., Aspelmeyer, M., Painter, O. 2011; 478 (7367): 89-92

  View details for DOI 10.1038/nature10461

  View details for Web of Science ID 000295575400040

• Electromagnetically induced transparency and slow light with optomechanics NATURE Safavi-Naeini, A. H., Alegre, T. P., Chan, J., Eichenfield, M., Winger, M., Lin, Q., Hill, J. T., Chang, D. E., Painter, O. 2011; 472 (7341): 69-73

  Abstract

  Controlling the interaction between localized optical and mechanical excitations has recently become possible following advances in micro- and nanofabrication techniques. So far, most experimental studies of optomechanics have focused on measurement and control of the mechanical subsystem through its interaction with optics, and have led to the experimental demonstration of dynamical back-action cooling and optical rigidity of the mechanical system. Conversely, the optical response of these systems is also modified in the presence of mechanical interactions, leading to effects such as electromagnetically induced transparency (EIT) and parametric normal-mode splitting. In atomic systems, studies of slow and stopped light (applicable to modern optical networks and future quantum networks) have thrust EIT to the forefront of experimental study during the past two decades. Here we demonstrate EIT and tunable optical delays in a nanoscale optomechanical crystal, using the optomechanical nonlinearity to control the velocity of light by way of engineered photon-phonon interactions. Our device is fabricated by simply etching holes into a thin film of silicon. At low temperature (8.7 kelvin), we report an optically tunable delay of 50 nanoseconds with near-unity optical transparency, and superluminal light with a 1.4 microsecond signal advance. These results, while indicating significant progress towards an integrated quantum optomechanical memory, are also relevant to classical signal processing applications. Measurements at room temperature in the analogous regime of electromagnetically induced absorption show the utility of these chip-scale optomechanical systems for optical buffering, amplification, and filtering of microwave-over-optical signals.

  View details for DOI 10.1038/nature09933

  View details for Web of Science ID 000289199400038

  View details for PubMedID 21412237

• Quasi-two-dimensional optomechanical crystals with a complete phononic bandgap OPTICS EXPRESS Alegre, T. P., Safavi-Naeini, A., Winger, M., Painter, O. 2011; 19 (6): 5658-5669

  Abstract

  A fully planar two-dimensional optomechanical crystal formed in a silicon microchip is used to create a structure devoid of phonons in the GHz frequency range. A nanoscale photonic crystal cavity is placed inside the phononic bandgap crystal in order to probe the properties of the localized acoustic modes. By studying the trends in mechanical damping, mode density, and optomechanical coupling strength of the acoustic resonances over an array of structures with varying geometric properties, clear evidence of a complete phononic bandgap is shown.

  View details for Web of Science ID 000288871300106

  View details for PubMedID 21445206

• Slowing and stopping light using an optomechanical crystal array NEW JOURNAL OF PHYSICS Chang, D. E., Safavi-Naeini, A. H., Hafezi, M., Painter, O. 2011; 13

  View details for DOI 10.1088/1367-2630/13/2/023003

  View details for Web of Science ID 000287852800003

• Proposal for an optomechanical traveling wave phonon-photon translator NEW JOURNAL OF PHYSICS Safavi-Naeini, A. H., Painter, O. 2011; 13

  View details for DOI 10.1088/1367-2630/13/1/013017

  View details for Web of Science ID 000288903600017

• Tunable 2D Photonic Crystal Cavities for Cavity Electro-Optomechanics 2011 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) Winger, M., Alegre, T. P., Safavi-Naeini, A. H., Painter, O. 2011

  View details for Web of Science ID 000295612401340

• Full Phononic Bandgap in 2D-Optomechanical Crystals 2011 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) Alegre, T. P., Safavi-Naeini, A. H., Winger, M., Painter, O. 2011

  View details for Web of Science ID 000295612400058

• Optomechanics in an ultrahigh-Q two-dimensional photonic crystal cavity APPLIED PHYSICS LETTERS Safavi-Naeini, A. H., Alegre, T. P., Winger, M., Painter, O. 2010; 97 (18)

  View details for DOI 10.1063/1.3507288

  View details for Web of Science ID 000283934100006

• Design of optomechanical cavities and waveguides on a simultaneous bandgap phononic-photonic crystal slab OPTICS EXPRESS Safavi-Naeini, A. H., Painter, O. 2010; 18 (14): 14926-14943

  Abstract

  In this paper we study and design quasi-2D optomechanical crystals, waveguides, and resonant cavities formed from patterned slabs. Two-dimensional periodicity allows for in-plane pseudo-bandgaps in frequency where resonant optical and mechanical excitations localized to the slab are forbidden. By tailoring the unit cell geometry, we show that it is possible to have a slab crystal with simultaneous optical and mechanical pseudo-bandgaps, and for which optical waveguiding is not compromised. We then use these crystals to design optomechanical cavities in which strongly interacting, co-localized photonic-phononic resonances occur. A resonant cavity structure formed by perturbing a ;;linear defect' waveguide of optical and acoustic waves in a silicon optomechanical crystal slab is shown to support an optical resonance at wavelength lambda(0) approximately 1.5 mum and a mechanical resonance of frequency omega(m)/2pi approximately 9.5 GHz. These resonances, due to the simultaneous pseudo-bandgap of the waveguide structure, are simulated to have optical and mechanical radiation-limited Q-factors greater than 10(7). The optomechanical coupling of the optical and acousticresonances in this cavity due to radiation pressure is also studied, with a quantum conversion rate, corresponding to the scattering rate of a single cavity photon via a single cavity phonon, calculated to be g/2pi = 292 kHz.

  View details for DOI 10.1364/OE.18.014926

  View details for Web of Science ID 000279639900065

  View details for PubMedID 20639979

• Optical Probing and Actuation of Microwave Frequency Phononic Crystal Resonators without Clamping Losses 2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS) Eichenfield, M., Chan, J., Safavi-Naeini, A. H., Painter, O. J. 2010

  View details for Web of Science ID 000290513602056

• Slowing and stopping light with an optomechanical crystal array THIRD INTERNATIONAL WORKSHOP ON THEORETICAL AND COMPUTATIONAL NANOPHOTONICS - TACONA-PHOTONICS 2010 Chang, D. E., Safavi-Naeini, A. H., Hafezi, M., Painter, O. 2010; 1291: 13-17

  View details for Web of Science ID 000287019200005

• Efficient On-Chip Phonon-Photon Translation 2010 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO) AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (QELS) Safavi-Naeini, A. H., Alegre, T. P., Painter, O. J. 2010

  View details for Web of Science ID 000290513602052

• Surface-plasmon mode hybridization in subwavelength microdisk lasers APPLIED PHYSICS LETTERS Perahia, R., Alegre, T. P., Safavi-Naeini, A. H., Painter, O. 2009; 95 (20)

  View details for DOI 10.1063/1.3266843

  View details for Web of Science ID 000272052200014

• Modeling dispersive coupling and losses of localized optical and mechanical modes in optomechanical crystals OPTICS EXPRESS Eichenfield, M., Chan, J., Safavi-Naeini, A. H., Vahala, K. J., Painter, O. 2009; 17 (22): 20078-20098

  Abstract

  Periodically structured materials can sustain both optical and mechanical excitations which are tailored by the geometry. Here we analyze the properties of dispersively coupled planar photonic and phononic crystals: optomechanical crystals. In particular, the properties of co-resonant optical and mechanical cavities in quasi-1D (patterned nanobeam) and quasi-2D (patterned membrane) geometries are studied. It is shown that the mechanical Q and optomechanical coupling in these structures can vary by many orders of magnitude with modest changes in geometry. An intuitive picture is developed based upon a perturbation theory for shifting material boundaries that allows the optomechanical properties to be designed and optimized. Several designs are presented with mechanical frequency approximately 1-10 GHz, optical Q-factor Qo > 107, motional masses meff approximately 100 femtograms, optomechanical coupling length LOM < 5 microm, and clampinig losses that are exponentially suppressed with increasing number of phononic crystal periods (radiation-limited mechanical Q-factor Qm > 107 for total device size less than 30 microm).

  View details for DOI 10.1364/OE.17.020078

  View details for Web of Science ID 000271629200080

  View details for PubMedID 19997232

• Surface Plasmon Waveguide Mode Hybridization and Lasing in Sub-wavelength Microdisks at 1.3 mu m 2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5 Perahia, R., Alegre, T. P., Safavi-Naeini, A., Painter, O. 2009: 3232-3233

  View details for Web of Science ID 000274751302602