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  • Matter waves and clocks do not observe uniform gravitational fields PHYSICA SCRIPTA Asenbaum, P., Overstreet, C., Kasevich, M. A. 2024; 99 (4)
  • Inference of gravitational field superposition from quantum measurements PHYSICAL REVIEW D Overstreet, C., Curti, J., Kim, M., Asenbaum, P., Kasevich, M. A., Giacomini, F. 2023; 108 (8)
  • Multi-pass Imaging Flow Cytometry. Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada Reynolds, J. L., Israel, Y., Kasevich, M. A. 2023; 29 (Supplement_1): 1064-1065

    View details for DOI 10.1093/micmic/ozad067.545

    View details for PubMedID 37613229

  • Wide-field fluorescence lifetime imaging of neuron spiking and subthreshold activity in vivo. Science (New York, N.Y.) Bowman, A. J., Huang, C., Schnitzer, M. J., Kasevich, M. A. 2023; 380 (6651): 1270-1275

    Abstract

    The development of voltage-sensitive fluorescent probes suggests fluorescence lifetime as a promising readout for electrical activity in biological systems. Existing approaches fail to achieve the speed and sensitivity required for voltage imaging in neuroscience applications. We demonstrated that wide-field electro-optic fluorescence lifetime imaging microscopy (EO-FLIM) allows lifetime imaging at kilohertz frame-acquisition rates, spatially resolving action potential propagation and subthreshold neural activity in live adult Drosophila. Lifetime resolutions of <5 picoseconds at 1 kilohertz were achieved for single-cell voltage recordings. Lifetime readout is limited by photon shot noise, and the method provides strong rejection of motion artifacts and technical noise sources. Recordings revealed local transmembrane depolarizations, two types of spikes with distinct fluorescence lifetimes, and phase locking of spikes to an external mechanical stimulus.

    View details for DOI 10.1126/science.adf9725

    View details for PubMedID 37347862

  • Continuous wave multi-pass imaging flow cytometry OPTICA Israel, Y., Reynolds, J. L., Klopfer, B. B., Kasevich, M. A. 2023; 10 (4): 491-496
  • Robust Optimized Pulse Schemes for Atomic Fountain Interferometry ATOMS Goerz, M. H., Kasevich, M. A., Malinovsky, V. S. 2023; 11 (2)
  • Nanosecond Photoemission near the Potential Barrier of a Schottky Emitter PHYSICAL REVIEW APPLIED Reynolds, J. L., Israel, Y., Bowman, A. J., Klopfer, B. B., Kasevich, M. A. 2023; 19 (1)
  • Distributed quantum sensing with mode-entangled spin-squeezed atomic states. Nature Malia, B. K., Wu, Y., Martinez-Rincon, J., Kasevich, M. A. 2022

    Abstract

    Quantum sensors are used for precision timekeeping, field sensing and quantum communication1-3. Comparisons among a distributed network of these sensors are capable of, for example, synchronizing clocks at different locations4-8. The performance of a sensor network is limited by technical challenges as well as the inherent noise associated with the quantum states used to realize the network9. For networks with only spatially localized entanglement at each node, the noise performance of the network improves at best with the square root of the number of nodes10. Here we demonstrate that spatially distributed entanglement between network nodes offers better scaling with network size. A shared quantum nondemolition measurement entangles a clock network with up to four nodes. This network provides up to 4.5decibels better precision than one without spatially distributed entanglement, and 11.6decibels improvement as compared to a network of sensors operating at the quantum projection noise limit. We demonstrate the generality of the approach with atomic clock and atomic interferometer protocols, in scientific and technologically relevant configurations optimized for intrinsically differential comparisons of sensor outputs.

    View details for DOI 10.1038/s41586-022-05363-z

    View details for PubMedID 36418400

  • Utilizing machine learning to improve the precision of fluorescence imaging of cavity-generated spin squeezed states PHYSICAL REVIEW A Malia, B. K., Wu, Y., Martinez-Rincon, J., Kasevich, M. A. 2022; 105 (1)
  • Observation of a gravitational Aharonov-Bohm effect. Science (New York, N.Y.) Overstreet, C., Asenbaum, P., Curti, J., Kim, M., Kasevich, M. A. 1800; 375 (6577): 226-229

    Abstract

    [Figure: see text].

    View details for DOI 10.1126/science.abl7152

    View details for PubMedID 35025635

  • Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100) QUANTUM SCIENCE AND TECHNOLOGY Abe, M., Adamson, P., Borcean, M., Bortoletto, D., Bridges, K., Carman, S. P., Chattopadhyay, S., Coleman, J., Curfman, N. M., DeRose, K., Deshpande, T., Dimopoulos, S., Foot, C. J., Frisch, J. C., Garber, B. E., Geer, S., Gibson, V., Glick, J., Graham, P. W., Hahn, S. R., Harnik, R., Hawkins, L., Hindley, S., Hogan, J. M., Jiang, Y., Kasevich, M. A., Kellett, R. J., Kiburg, M., Kovachy, T., Lykken, J. D., March-Russell, J., Mitchell, J., Murphy, M., Nantel, M., Nobrega, L. E., Plunkett, R. K., Rajendran, S., Rudolph, J., Sachdeva, N., Safdari, M., Santucci, J. K., Schwartzman, A. G., Shipsey, I., Swan, H., Valerio, L. R., Vasonis, A., Wang, Y., Wilkason, T. 2021; 6 (4)
  • Resonant Electro-Optic Imaging for Microscopy at Nanosecond Resolution. ACS nano Bowman, A. J., Kasevich, M. A. 2021

    Abstract

    We demonstrate an electro-optic wide-field method to enable fluorescence lifetime microscopy (FLIM) with high throughput and single-molecule sensitivity. Resonantly driven Pockels cells are used to efficiently gate images at 39 MHz, allowing fluorescence lifetime to be captured on standard camera sensors. Lifetime imaging of single molecules is enabled in wide field with exposure times of less than 100 ms. This capability allows combination of wide-field FLIM with single-molecule super-resolution localization microscopy. Fast single-molecule dynamics such as FRET and molecular binding events are captured from wide-field images without prior spatial knowledge. A lifetime sensitivity of 1.9 times the photon shot-noise limit is achieved, and high throughput is shown by acquiring wide-field FLIM images with millisecond exposure and >108 photons per frame. Resonant electro-optic FLIM allows lifetime contrast in any wide-field microscopy method.

    View details for DOI 10.1021/acsnano.1c04470

    View details for PubMedID 34546704

  • Information transfer as a framework for optimized phase imaging OPTICA Koppell, S., Kasevich, M. 2021; 8 (4): 493-501
  • Fast pulse shaping for a novel gated electron mirror REVIEW OF SCIENTIFIC INSTRUMENTS Klopfer, B. B., Koppell, S. A., Bowman, A. J., Israel, Y., Kasevich, M. A. 2021; 92 (4)

    View details for DOI 10.1063/5.0039523

    View details for Web of Science ID 000638192900001

  • Fast pulse shaping for a novel gated electron mirror. The Review of scientific instruments Klopfer, B. B., Koppell, S. A., Bowman, A. J., Israel, Y., Kasevich, M. A. 2021; 92 (4): 043705

    Abstract

    We present the design and prototype of a switchable electron mirror, along with a technique for driving it with an arbitrary pulse shape. We employ a general technique for electronic pulse-shaping, where high fidelity of the pulse shape is required, but the characteristics of the system, which are possibly nonlinear, are not known. This driving technique uses an arbitrary waveform generator to pre-compensate the pulse, with a simple iterative algorithm used to generate the input waveform. This is a broadly applicable, general method for arbitrary pulse shaping. Driving our switchable electron mirror with a flat-top pulse, we demonstrate an improvement in rms error of roughly two orders of magnitude compared to an uncompensated waveform. Our results demonstrate the feasibility of high fidelity waveform reproduction in the presence of nonidealities, with immediate applications in the realization of novel electron optical components.

    View details for DOI 10.1063/5.0039523

    View details for PubMedID 34243461

  • Physically significant phase shifts in matter-wave interferometry AMERICAN JOURNAL OF PHYSICS Overstreet, C., Asenbaum, P., Kasevich, M. A. 2021; 89 (3): 324–32

    View details for DOI 10.1119/10.0002638

    View details for Web of Science ID 000621569800012

  • 40 W, 780 nm laser system with compensated dual beam splitters for atom interferometry OPTICS LETTERS Kim, M., Notermans, R., Overstreet, C., Curti, J., Asenbaum, P., Kasevich, M. A. 2020; 45 (23): 6555–58

    Abstract

    We demonstrate a narrow-linewidth 780 nm laser system with up to 40W power and a frequency modulation bandwidth of 230 MHz. Efficient overlap on nonlinear optical elements combines two pairs of phase-locked frequency components into a single beam. Serrodyne modulation with a high-quality sawtooth waveform is used to perform frequency shifts with >96.5% efficiency over tens of megahertz. This system enables next-generation atom interferometry by delivering simultaneous, Stark-shift-compensated dual beam splitters while minimizing spontaneous emission.

    View details for DOI 10.1364/OL.404430

    View details for Web of Science ID 000595610900055

    View details for PubMedID 33258860

  • High-extinction electron pulses by laser-triggered emission from a Schottky emitter APPLIED PHYSICS LETTERS Israel, Y., Bowman, A. J., Klopfer, B. B., Koppell, S. A., Kasevich, M. A. 2020; 117 (19)

    View details for DOI 10.1063/5.0028493

    View details for Web of Science ID 000590844900001

  • Retrieval of cavity-generated atomic spin squeezing after free-space release PHYSICAL REVIEW A Wu, Y., Krishnakumar, R., Martinez-Rincon, J., Malia, B. K., Hosten, O., Kasevich, M. A. 2020; 102 (1)
  • Free Space Ramsey Spectroscopy in Rubidium with Noise below the Quantum Projection Limit. Physical review letters Malia, B. K., Martínez-Rincón, J., Wu, Y., Hosten, O., Kasevich, M. A. 2020; 125 (4): 043202

    Abstract

    We demonstrate the utility of optical cavity generated spin-squeezed states in free space atomic fountain clocks in ensembles of 390 000 ^{87}Rb atoms. Fluorescence imaging, correlated to an initial quantum nondemolition measurement, is used for population spectroscopy after the atoms are released from a confining lattice. For a free fall time of 4 milliseconds, we resolve a single-shot phase sensitivity of 814(61) microradians, which is 5.8(0.6) decibels (dB) below the quantum projection limit. We observe that this squeezing is preserved as the cloud expands to a roughly 200  μm radius and falls roughly 300  μm in free space. Ramsey spectroscopy with 240 000 atoms at a 3.6 ms Ramsey time results in a single-shot fractional frequency stability of 8.4(0.2)×10^{-12}, 3.8(0.2) dB below the quantum projection limit. The sensitivity and stability are limited by the technical noise in the fluorescence detection protocol and the microwave system, respectively.

    View details for DOI 10.1103/PhysRevLett.125.043202

    View details for PubMedID 32794788

  • Free Space Ramsey Spectroscopy in Rubidium with Noise below the Quantum Projection Limit PHYSICAL REVIEW LETTERS Malia, B. K., Martinez-Rincon, J., Wu, Y., Hosten, O., Kasevich, M. A. 2020; 125 (4)
  • AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space EPJ QUANTUM TECHNOLOGY El-Neaj, Y., Alpigiani, C., Amairi-Pyka, S., Araujo, H., Balaz, A., Bassi, A., Bathe-Peters, L., Battelier, B., Belic, A., Bentine, E., Bernabeu, J., Bertoldi, A., Bingham, R., Blas, D., Bolpasi, V., Bongs, K., Bose, S., Bouyer, P., Bowcock, T., Bowden, W., Buchmueller, O., Burrage, C., Calmet, X., Canuel, B., Caramete, L., Carroll, A., Cella, G., Charmandaris, V., Chattopadhyay, S., Chen, X., Chiofalo, M., Coleman, J., Cotter, J., Cui, Y., Derevianko, A., De Roeck, A., Djordjevic, G. S., Dornan, P., Doser, M., Drougkakis, I., Dunningham, J., Dutan, I., Easo, S., Elertas, G., Ellis, J., El Sawy, M., Fassi, F., Felea, D., Feng, C., Flack, R., Foot, C., Fuentes, I., Gaaloul, N., Gauguet, A., Geiger, R., Gibson, V., Giudice, G., Goldwin, J., Grachov, O., Graham, P. W., Grasso, D., Van der Grinten, M., Guendogan, M., Haehnelt, M. G., Harte, T., Hees, A., Hobson, R., Hogan, J., Holst, B., Holynski, M., Kasevich, M., Kavanagh, B. J., Von Klitzing, W., Kovachy, T., Krikler, B., Krutzik, M., Lewicki, M., Lien, Y., Liu, M., Luciano, G., Magnon, A., Mahmoud, M., Malik, S., McCabe, C., Mitchell, J., Pahl, J., Pal, D., Pandey, S., Papazoglou, D., Paternostro, M., Penning, B., Peters, A., Prevedelli, M., Puthiya-Veettil, V., Quenby, J., Rasel, E., Ravenhall, S., Ringwood, J., Roura, A., Sabulsky, D., Sameed, M., Sauer, B., Schaffer, S., Schiller, S., Schkolnik, V., Schlippert, D., Schubert, C., Sfar, H., Shayeghi, A., Shipsey, I., Signorini, C., Singh, Y., Soares-Santos, M., Sorrentino, F., Sumner, T., Tassis, K., Tentindo, S., Tino, G., Tinsley, J. N., Unwin, J., Valenzuela, T., Vasilakis, G., Vaskonen, V., Vogt, C., Webber-Date, A., Wenzlawski, A., Windpassinger, P., Woltmann, M., Yazgan, E., Zhan, M., Zou, X., Zupan, J. 2020; 7 (1)
  • Atom-Interferometric Test of the Equivalence Principle at the 10^{-12} Level. Physical review letters Asenbaum, P. n., Overstreet, C. n., Kim, M. n., Curti, J. n., Kasevich, M. A. 2020; 125 (19): 191101

    Abstract

    We use a dual-species atom interferometer with 2 s of free-fall time to measure the relative acceleration between ^{85}Rb and ^{87}Rb wave packets in the Earth's gravitational field. Systematic errors arising from kinematic differences between the isotopes are suppressed by calibrating the angles and frequencies of the interferometry beams. We find an Eötvös parameter of η=[1.6±1.8(stat)±3.4(syst)]×10^{-12}, consistent with zero violation of the equivalence principle. With a resolution of up to 1.4×10^{-11}  g per shot, we demonstrate a sensitivity to η of 5.4×10^{-11}/sqrt[Hz].

    View details for DOI 10.1103/PhysRevLett.125.191101

    View details for PubMedID 33216577

  • SAGE: A proposal for a space atomic gravity explorer EUROPEAN PHYSICAL JOURNAL D Tino, G. M., Bassi, A., Bianco, G., Bongs, K., Bouyer, P., Cacciapuoti, L., Capozziello, S., Chen, X., Chiofalo, M. L., Derevianko, A., Ertmer, W., Gaaloul, N., Gill, P., Graham, P. W., Hogan, J. M., Iess, L., Kasevich, M. A., Katori, H., Klempt, C., Lu, X., Ma, L., Mueller, H., Newbury, N. R., Oates, C. W., Peters, A., Poli, N., Rasel, E. M., Rosi, G., Roura, A., Salomon, C., Schiller, S., Schleich, W., Schlippert, D., Schreck, F., Schubert, C., Sorrentino, F., Sterr, U., Thomsen, J. W., Vallone, G., Vetrano, F., Villoresi, P., von Klitzing, W., Wilkowski, D., Wolf, P., Ye, J., Yu, N., Zhan, M. 2019; 73 (11)
  • Design for a 10keV multi-pass transmission electron microscope. Ultramicroscopy Koppell, S. A., Mankos, M., Bowman, A. J., Israel, Y., Juffmann, T., Klopfer, B. B., Kasevich, M. A. 2019; 207: 112834

    Abstract

    Multi-pass transmission electron microscopy (MPTEM) has been proposed as a way to reduce damage to radiation-sensitive materials. For the field of cryo-electron microscopy (cryo-EM), this would significantly reduce the number of projections needed to create a 3D model and would allow the imaging of lower-contrast, more heterogeneous samples. We have designed a 10keV proof-of-concept MPTEM. The column features fast-switching gated electron mirrors which cause each electron to interrogate the sample multiple times. A linear approximation for the multi-pass contrast transfer function (CTF) is developed to explain how the resolution depends on the number of passes through the sample.

    View details for DOI 10.1016/j.ultramic.2019.112834

    View details for PubMedID 31520925

  • Electro-optic imaging enables efficient wide-field fluorescence lifetime microscopy. Nature communications Bowman, A. J., Klopfer, B. B., Juffmann, T. n., Kasevich, M. A. 2019; 10 (1): 4561

    Abstract

    Nanosecond temporal resolution enables new methods for wide-field imaging like time-of-flight, gated detection, and fluorescence lifetime. The optical efficiency of existing approaches, however, presents challenges for low-light applications common to fluorescence microscopy and single-molecule imaging. We demonstrate the use of Pockels cells for wide-field image gating with nanosecond temporal resolution and high photon collection efficiency. Two temporal frames are obtained by combining a Pockels cell with a pair of polarizing beam-splitters. We show multi-label fluorescence lifetime imaging microscopy (FLIM), single-molecule lifetime spectroscopy, and fast single-frame FLIM at the camera frame rate with 103-105 times higher throughput than single photon counting. Finally, we demonstrate a space-to-time image multiplexer using a re-imaging optical cavity with a tilted mirror to extend the Pockels cell technique to multiple temporal frames. These methods enable nanosecond imaging with standard optical systems and sensors, opening a new temporal dimension for wide-field low-light microscopy.

    View details for DOI 10.1038/s41467-019-12535-5

    View details for PubMedID 31594938

  • Full-field cavity enhanced microscopy techniques JOURNAL OF PHYSICS-PHOTONICS Nimmrichter, S., Chen, C., Klopfer, B. B., Kasevich, M. A., Juffmann, T. 2019; 1 (1)
  • Effective Inertial Frame in an Atom Interferometric Test of the Equivalence Principle PHYSICAL REVIEW LETTERS Overstreet, C., Asenbaum, P., Kovachy, T., Notermans, R., Hogan, J. M., Kasevich, M. A. 2018; 120 (18): 183604

    Abstract

    In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. Here we demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. Using this method, we suppress the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by 2 orders of magnitude and precisely measure these differences. We realize a relative precision of Δg/g≈6×10^{-11} per shot, which improves on the best previous result for a dual-species atom interferometer by more than 3 orders of magnitude. By reducing gravity gradient systematic errors to one part in 10^{13}, these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests.

    View details for PubMedID 29775337

  • Multi-pass transmission electron microscopy SCIENTIFIC REPORTS Juffmann, T., Koppell, S. A., Klopfer, B. B., Ophus, C., Glaeser, R. M., Kasevich, M. A. 2017; 7

    Abstract

    Feynman once asked physicists to build better electron microscopes to be able to watch biology at work. While electron microscopes can now provide atomic resolution, electron beam induced specimen damage precludes high resolution imaging of sensitive materials, such as single proteins or polymers. Here, we use simulations to show that an electron microscope based on a multi-pass measurement protocol enables imaging of single proteins, without averaging structures over multiple images. While we demonstrate the method for particular imaging targets, the approach is broadly applicable and is expected to improve resolution and sensitivity for a range of electron microscopy imaging modalities, including, for example, scanning and spectroscopic techniques. The approach implements a quantum mechanically optimal strategy which under idealized conditions can be considered interaction-free.

    View details for DOI 10.1038/s41598-017-01841-x

    View details for Web of Science ID 000400886100039

    View details for PubMedID 28490730

  • Phase Shift in an Atom Interferometer due to Spacetime Curvature across its Wave Function PHYSICAL REVIEW LETTERS Asenbaum, P., Overstreet, C., Kovachy, T., Brown, D. D., Hogan, J. M., Kasevich, M. A. 2017; 118 (18)

    Abstract

    Spacetime curvature induces tidal forces on the wave function of a single quantum system. Using a dual light-pulse atom interferometer, we measure a phase shift associated with such tidal forces. The macroscopic spatial superposition state in each interferometer (extending over 16 cm) acts as a nonlocal probe of the spacetime manifold. Additionally, we utilize the dual atom interferometer as a gradiometer for precise gravitational measurements.

    View details for DOI 10.1103/PhysRevLett.118.183602

    View details for Web of Science ID 000400672600002

    View details for PubMedID 28524681

  • Bell Correlations in Spin-Squeezed States of 500 000 Atoms PHYSICAL REVIEW LETTERS Engelsen, N. J., Krishnakumar, R., Hosten, O., Kasevich, M. A. 2017; 118 (14)

    Abstract

    Bell correlations, indicating nonlocality in composite quantum systems, were until recently only seen in small systems. Here, we demonstrate Bell correlations in squeezed states of 5×10^{5} ^{87}Rb atoms. The correlations are inferred using collective measurements as witnesses and are statistically significant to 124 standard deviations. The states are both generated and characterized using optical-cavity aided measurements.

    View details for DOI 10.1103/PhysRevLett.118.140401

    View details for Web of Science ID 000399395500001

    View details for PubMedID 28430469

  • Sub-shot noise measurement strategies for precision atomic sensors Kasevich, M., IEEE IEEE. 2017
  • Iterative creation and sensing of twisted light OPTICS LETTERS Klopfer, B. B., Juffmann, T., Kasevich, M. A. 2016; 41 (24): 5744-5747

    Abstract

    The iterative interaction of a photon with a sample can lead to increased sensitivity in measuring the properties of the samples, such as its refractive index or birefringence. Here we show that this principle can also be used to generate and sense states of light. In particular, we demonstrate a technique to generate states with high orbital angular momentum using a single-vortex phase plate (VPP). This is accomplished by placing the phase plate in a self-imaging cavity such that light interacts with it multiple times; for an ideal phase plate, this is equivalent to iterative applications of the angular momentum operator. Using a discrete VPP, we show that our setup realizes a high-dimensional generalization of the Pauli matrix σx, and that the created states show sub-diffraction limited features that might find applications in structured illumination microscopy.

    View details for DOI 10.1364/OL.41.005744

    View details for Web of Science ID 000390403600032

    View details for PubMedID 27973521

  • Resonant mode for gravitational wave detectors based on atom interferometry PHYSICAL REVIEW D Graham, P. W., Hogan, J. M., Kasevich, M. A., Rajendran, S. 2016; 94 (10)
  • Atom-interferometric gravitational-wave detection using heterodyne laser links PHYSICAL REVIEW A Hogan, J. M., Kasevich, M. A. 2016; 94 (3)
  • Multi-pass microscopy NATURE COMMUNICATIONS Juffmann, T., Klopfer, B. B., Frankort, T. L., Haslinger, P., Kasevich, M. A. 2016; 7

    Abstract

    Microscopy of biological specimens often requires low light levels to avoid damage. This yields images impaired by shot noise. An improved measurement accuracy at the Heisenberg limit can be achieved exploiting quantum correlations. If sample damage is the limiting resource, an equivalent limit can be reached by passing photons through a specimen multiple times sequentially. Here we use self-imaging cavities and employ a temporal post-selection scheme to present full-field multi-pass polarization and transmission micrographs with variance reductions of 4.4±0.8 dB (11.6±0.8 dB in a lossless setup) and 4.8±0.8 dB, respectively, compared with the single-pass shot-noise limit. If the accuracy is limited by the number of detected probe particles, our measurements show a variance reduction of 25.9±0.9 dB. The contrast enhancement capabilities in imaging and in diffraction studies are demonstrated with nanostructured samples and with embryonic kidney 293T cells. This approach to Heisenberg-limited microscopy does not rely on quantum state engineering.

    View details for DOI 10.1038/ncomms12858

    View details for Web of Science ID 000385383600005

    View details for PubMedID 27670525

    View details for PubMedCentralID PMC5052624

  • Quantum phase magnification SCIENCE Hosten, O., Krishnakumar, R., Engelsen, N. J., Kasevich, M. A. 2016; 352 (6293): 1552-1555

    Abstract

    Quantum metrology exploits entangled states of particles to improve sensing precision beyond the limit achievable with uncorrelated particles. All previous methods required detection noise levels below this standard quantum limit to realize the benefits of the intrinsic sensitivity provided by these states. We experimentally demonstrate a widely applicable method for entanglement-enhanced measurements without low-noise detection. The method involves an intermediate quantum phase magnification step that eases implementation complexity. We used it to perform squeezed-state metrology 8 decibels below the standard quantum limit with a detection system that has a noise floor 10 decibels above the standard quantum limit.

    View details for DOI 10.1126/science.aaf3397

    View details for Web of Science ID 000378346500037

    View details for PubMedID 27339982

  • Designs for a quantum electron microscope ULTRAMICROSCOPY Kruit, P., Hobbs, R. G., Kim, C., Yang, Y., Manfrinato, V. R., Hammer, J., Thomas, S., Weber, P., KLOPFER, B., Kohstall, C., Juffmann, T., Kasevich, M. A., Hommelhoff, P., Berggren, K. K. 2016; 164: 31-45

    Abstract

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This 'quantum weirdness' could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or "quantum electron microscope". A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope.

    View details for DOI 10.1016/j.ultramic.2016.03.004

    View details for PubMedID 26998703

  • Single-shot simulations of dynamic quantum many-body systems NATURE PHYSICS Sakmann, K., Kasevich, M. 2016; 12 (5): 451-?

    View details for DOI 10.1038/NPHYS3631

    View details for Web of Science ID 000375255000014

  • Measurement noise 100 times lower than the quantum-projection limit using entangled atoms NATURE Hosten, O., Engelsen, N. J., Krishnakumar, R., Kasevich, M. A. 2016; 529 (7587): 505-?

    Abstract

    Quantum metrology uses quantum entanglement--correlations in the properties of microscopic systems--to improve the statistical precision of physical measurements. When measuring a signal, such as the phase shift of a light beam or an atomic state, a prominent limitation to achievable precision arises from the noise associated with the counting of uncorrelated probe particles. This noise, commonly referred to as shot noise or projection noise, gives rise to the standard quantum limit (SQL) to phase resolution. However, it can be mitigated down to the fundamental Heisenberg limit by entangling the probe particles. Despite considerable experimental progress in a variety of physical systems, a question that persists is whether these methods can achieve performance levels that compare favourably with optimized conventional (non-entangled) systems. Here we demonstrate an approach that achieves unprecedented levels of metrological improvement using half a million (87)Rb atoms in their 'clock' states. The ensemble is 20.1 ± 0.3 decibels (100-fold) spin-squeezed via an optical-cavity-based measurement. We directly resolve small microwave-induced rotations 18.5 ± 0.3 decibels (70-fold) beyond the SQL. The single-shot phase resolution of 147 microradians achieved by the apparatus is better than that achieved by the best engineered cold atom sensors despite lower atom numbers. We infer entanglement of more than 680 ± 35 particles in the atomic ensemble. Applications include atomic clocks, inertial sensors, and fundamental physics experiments such as tests of general relativity or searches for electron electric dipole moment. To this end, we demonstrate an atomic clock measurement with a quantum enhancement of 10.5 ± 0.3 decibels (11-fold), limited by the phase noise of our microwave source.

    View details for DOI 10.1038/nature16176

    View details for Web of Science ID 000368673800032

  • Measurement noise 100 times lower than the quantum-projection limit using entangled atoms. Nature Hosten, O., Engelsen, N. J., Krishnakumar, R., Kasevich, M. A. 2016; 529 (7587): 505-8

    Abstract

    Quantum metrology uses quantum entanglement--correlations in the properties of microscopic systems--to improve the statistical precision of physical measurements. When measuring a signal, such as the phase shift of a light beam or an atomic state, a prominent limitation to achievable precision arises from the noise associated with the counting of uncorrelated probe particles. This noise, commonly referred to as shot noise or projection noise, gives rise to the standard quantum limit (SQL) to phase resolution. However, it can be mitigated down to the fundamental Heisenberg limit by entangling the probe particles. Despite considerable experimental progress in a variety of physical systems, a question that persists is whether these methods can achieve performance levels that compare favourably with optimized conventional (non-entangled) systems. Here we demonstrate an approach that achieves unprecedented levels of metrological improvement using half a million (87)Rb atoms in their 'clock' states. The ensemble is 20.1 ± 0.3 decibels (100-fold) spin-squeezed via an optical-cavity-based measurement. We directly resolve small microwave-induced rotations 18.5 ± 0.3 decibels (70-fold) beyond the SQL. The single-shot phase resolution of 147 microradians achieved by the apparatus is better than that achieved by the best engineered cold atom sensors despite lower atom numbers. We infer entanglement of more than 680 ± 35 particles in the atomic ensemble. Applications include atomic clocks, inertial sensors, and fundamental physics experiments such as tests of general relativity or searches for electron electric dipole moment. To this end, we demonstrate an atomic clock measurement with a quantum enhancement of 10.5 ± 0.3 decibels (11-fold), limited by the phase noise of our microwave source.

    View details for DOI 10.1038/nature16176

    View details for PubMedID 26751056

  • Engineering Spin-Squeezed States for Quantum-Enhanced Atom Interferometry Engelsen, N. J., Hosten, O., Krishnakumar, R., Kasevich, M. A., IEEE IEEE. 2016
  • Ultrafast Time-Resolved Photoelectric Emission PHYSICAL REVIEW LETTERS Juffmann, T., Klopfer, B. B., Skulason, G. E., Kealhofer, C., Xiao, F., Foreman, S. M., Kasevich, M. A. 2015; 115 (26)

    Abstract

    The emission times of laser-triggered electrons from a sharp tungsten tip are directly characterized under ultrafast, near-infrared laser excitation at Keldysh parameters of 6.6<γ<19.1. Emission delays up to 10 fs are observed, which are inferred from the energy gain of photoelectrons emitted into a synchronously driven microwave cavity. Few femtosecond timing resolution is achieved in a configuration capable of measuring timing shifts up to 55 ps. The technique can also be used to measure the microwave phase inside the cavity with a precision below 70 fs upon the energy resolved detection of a single electron.

    View details for DOI 10.1103/PhysRevLett.115.264803

    View details for Web of Science ID 000367385400001

  • Ultrafast Time-Resolved Photoelectric Emission. Physical review letters Juffmann, T., Klopfer, B. B., Skulason, G. E., Kealhofer, C., Xiao, F., Foreman, S. M., Kasevich, M. A. 2015; 115 (26): 264803

    Abstract

    The emission times of laser-triggered electrons from a sharp tungsten tip are directly characterized under ultrafast, near-infrared laser excitation at Keldysh parameters of 6.6<γ<19.1. Emission delays up to 10 fs are observed, which are inferred from the energy gain of photoelectrons emitted into a synchronously driven microwave cavity. Few femtosecond timing resolution is achieved in a configuration capable of measuring timing shifts up to 55 ps. The technique can also be used to measure the microwave phase inside the cavity with a precision below 70 fs upon the energy resolved detection of a single electron.

    View details for DOI 10.1103/PhysRevLett.115.264803

    View details for PubMedID 26764997

  • Quantum superposition at the half-metre scale NATURE Kovachy, T., Asenbaum, P., Overstreet, C., Donnelly, C. A., Dickerson, S. M., Sugarbaker, A., Hogan, J. M., Kasevich, M. A. 2015; 528 (7583): 530-?

    View details for DOI 10.1038/nature16155

    View details for Web of Science ID 000366991900047

    View details for PubMedID 26701053

  • Matter wave lensing to picokelvin temperatures. Physical review letters Kovachy, T., Hogan, J. M., Sugarbaker, A., Dickerson, S. M., Donnelly, C. A., Overstreet, C., Kasevich, M. A. 2015; 114 (14): 143004-?

    Abstract

    Using a matter wave lens and a long time of flight, we cool an ensemble of ^{87}Rb atoms in two dimensions to an effective temperature of less than 50_{-30}^{+50}  pK. A short pulse of red-detuned light generates an optical dipole force that collimates the ensemble. We also report a three-dimensional magnetic lens that substantially reduces the chemical potential of evaporatively cooled ensembles with a high atom number. By observing such low temperatures, we set limits on proposed modifications to quantum mechanics in the macroscopic regime. These cooling techniques yield bright, collimated sources for precision atom interferometry.

    View details for PubMedID 25910118

  • Matter Wave Lensing to Picokelvin Temperatures PHYSICAL REVIEW LETTERS Kovachy, T., Hogan, J. M., Sugarbaker, A., Dickerson, S. M., Donnelly, C. A., Overstreet, C., Kasevich, M. A. 2015; 114 (14)

    Abstract

    Using a matter wave lens and a long time of flight, we cool an ensemble of ^{87}Rb atoms in two dimensions to an effective temperature of less than 50_{-30}^{+50}  pK. A short pulse of red-detuned light generates an optical dipole force that collimates the ensemble. We also report a three-dimensional magnetic lens that substantially reduces the chemical potential of evaporatively cooled ensembles with a high atom number. By observing such low temperatures, we set limits on proposed modifications to quantum mechanics in the macroscopic regime. These cooling techniques yield bright, collimated sources for precision atom interferometry.

    View details for DOI 10.1103/PhysRevLett.114.143004

    View details for Web of Science ID 000352350000008

    View details for PubMedID 25910118

  • Testing gravity with cold-atom interferometers PHYSICAL REVIEW A Biedermann, G. W., Wu, X., Deslauriers, L., Roy, S., Mahadeswaraswamy, C., Kasevich, M. A. 2015; 91 (3)
  • Ultrafast oscilloscope based on laser-triggered field emitters OPTICS LETTERS Kealhofer, C., Klopfer, B. B., Skulason, G. E., Juffmann, T., Foreman, S. M., Kasevich, M. A. 2015; 40 (2): 260-263

    Abstract

    Laser-triggered electron emission from sharp metal tips has been demonstrated in recent years as a high brightness, ultrafast electron source. Its possible applications range from ultrafast electron microscopy to laser-based particle accelerators to electron interferometry. The ultrafast nature of the emission process allows for the sampling of an instantaneous radio frequency (RF) voltage that has been applied to a field emitter. For proof-of-concept, we use an RF signal derived from our laser's repetition rate, mapping a 9.28 GHz signal in 22.4 fs steps with 28 mv accuracy.

    View details for DOI 10.1364/OL.40.000260

    View details for Web of Science ID 000347939500034

  • Single-shot three-dimensional imaging of dilute atomic clouds OPTICS LETTERS Sakmann, K., Kasevich, M. 2014; 39 (18): 5317-5320

    Abstract

    Light field microscopy methods together with three-dimensional (3D) deconvolution can be used to obtain single-shot 3D images of atomic clouds. We demonstrate the method using a test setup that extracts 3D images from a fluorescent Rb87 atomic vapor.

    View details for DOI 10.1364/OL.39.005317

    View details for Web of Science ID 000341926500020

  • Many-atom-cavity QED system with homogeneous atom-cavity coupling OPTICS LETTERS Lee, J., Vrijsen, G., Teper, I., Hosten, O., Kasevich, M. A. 2014; 39 (13): 4005-4008

    Abstract

    We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

    View details for DOI 10.1364/OL.39.004005

    View details for Web of Science ID 000338933200080

    View details for PubMedID 24978793

  • Evaporative production of bright atomic solitons. Physical review letters Medley, P., Minar, M. A., Cizek, N. C., Berryrieser, D., Kasevich, M. A. 2014; 112 (6): 060401-?

    Abstract

    We describe a method of producing bright atomic solitons of 7Li through efficient radio frequency evaporation in a combined magnetic and optical trap. Solitons released in a magnetic waveguide propagate without dispersion, with lifetimes limited by two-body dipolar relaxation. We show how the method can be used to deterministically produce pairs of solitons.

    View details for PubMedID 24580683

  • Evaporative Production of Bright Atomic Solitons PHYSICAL REVIEW LETTERS Medley, P., Minar, M. A., Cizek, N. C., Berryrieser, D., Kasevich, M. A. 2014; 112 (6)
  • Ground-state fragmentation phase transition for attractive bosons in anisotropic traps PHYSICAL REVIEW A Cizek, N. C., Kasevich, M. A. 2013; 88 (6)
  • Zero-Dead-Time Operation of Interleaved Atomic Clocks PHYSICAL REVIEW LETTERS Biedermann, G. W., Takase, K., Wu, X., Deslauriers, L., Roy, S., Kasevich, M. A. 2013; 111 (17)

    Abstract

    We demonstrate a zero-dead-time operation of atomic clocks. This clock reduces sensitivity to local oscillator noise, integrating as nearly 1/τ whereas a clock with dead time integrates as 1/τ(1/2) under identical conditions. We contend that a similar scheme may be applied to improve the stability of optical clocks.

    View details for DOI 10.1103/PhysRevLett.111.170802

    View details for Web of Science ID 000326148600003

    View details for PubMedID 24206471

  • Enhanced atom interferometer readout through the application of phase shear. Physical review letters Sugarbaker, A., Dickerson, S. M., Hogan, J. M., Johnson, D. M., Kasevich, M. A. 2013; 111 (11): 113002-?

    Abstract

    We present a method for determining the phase and contrast of a single shot of an atom interferometer. The application of a phase shear across the atom ensemble yields a spatially varying fringe pattern at each output port, which can be imaged directly. This method is broadly relevant to atom-interferometric precision measurement, as we demonstrate in a 10 m ^{87}Rb atomic fountain by implementing an atom-interferometric gyrocompass with 10 mdeg precision.

    View details for PubMedID 24074082

  • Enhanced Atom Interferometer Readout through the Application of Phase Shear PHYSICAL REVIEW LETTERS Sugarbaker, A., Dickerson, S. M., Hogan, J. M., Johnson, D. M., Kasevich, M. A. 2013; 111 (11)

    Abstract

    We present a method for determining the phase and contrast of a single shot of an atom interferometer. The application of a phase shear across the atom ensemble yields a spatially varying fringe pattern at each output port, which can be imaged directly. This method is broadly relevant to atom-interferometric precision measurement, as we demonstrate in a 10 m ^{87}Rb atomic fountain by implementing an atom-interferometric gyrocompass with 10 mdeg precision.

    View details for DOI 10.1103/PhysRevLett.111.113002

    View details for Web of Science ID 000324233400007

    View details for PubMedID 24074082

  • Multiaxis inertial sensing with long-time point source atom interferometry. Physical review letters Dickerson, S. M., Hogan, J. M., Sugarbaker, A., Johnson, D. M., Kasevich, M. A. 2013; 111 (8): 083001-?

    Abstract

    We show that light-pulse atom interferometry with atomic point sources and spatially resolved detection enables multiaxis (two rotation, one acceleration) precision inertial sensing at long interrogation times. Using this method, we demonstrate a light-pulse atom interferometer for ^{87}Rb with 1.4 cm peak wave packet separation and a duration of 2T=2.3  s. The inferred acceleration sensitivity of each shot is 6.7×10^{-12}g, which improves on previous limits by more than 2 orders of magnitude. We also measure Earth's rotation rate with a precision of 200  nrad/s.

    View details for PubMedID 24010433

  • Multiaxis Inertial Sensing with Long-Time Point Source Atom Interferometry PHYSICAL REVIEW LETTERS Dickerson, S. M., Hogan, J. M., Sugarbaker, A., Johnson, D. M., Kasevich, M. A. 2013; 111 (8)

    Abstract

    We show that light-pulse atom interferometry with atomic point sources and spatially resolved detection enables multiaxis (two rotation, one acceleration) precision inertial sensing at long interrogation times. Using this method, we demonstrate a light-pulse atom interferometer for ^{87}Rb with 1.4 cm peak wave packet separation and a duration of 2T=2.3  s. The inferred acceleration sensitivity of each shot is 6.7×10^{-12}g, which improves on previous limits by more than 2 orders of magnitude. We also measure Earth's rotation rate with a precision of 200  nrad/s.

    View details for DOI 10.1103/PhysRevLett.111.083001

    View details for Web of Science ID 000323334900007

    View details for PubMedID 24010433

  • New method for gravitational wave detection with atomic sensors. Physical review letters Graham, P. W., Hogan, J. M., Kasevich, M. A., Rajendran, S. 2013; 110 (17): 171102-?

    Abstract

    Laser frequency noise is a dominant noise background for the detection of gravitational waves using long-baseline optical interferometry. Amelioration of this noise requires near simultaneous strain measurements on more than one interferometer baseline, necessitating, for example, more than two satellites for a space-based detector or two interferometer arms for a ground-based detector. We describe a new detection strategy based on recent advances in optical atomic clocks and atom interferometry which can operate at long baselines and which is immune to laser frequency noise. Laser frequency noise is suppressed because the signal arises strictly from the light propagation time between two ensembles of atoms. This new class of sensor allows sensitive gravitational wave detection with only a single baseline. This approach also has practical applications in, for example, the development of ultrasensitive gravimeters and gravity gradiometers.

    View details for PubMedID 23679702

  • New method for gravitational wave detection with atomic sensors. Physical review letters Graham, P. W., Hogan, J. M., Kasevich, M. A., Rajendran, S. 2013; 110 (17): 171102-?

    Abstract

    Laser frequency noise is a dominant noise background for the detection of gravitational waves using long-baseline optical interferometry. Amelioration of this noise requires near simultaneous strain measurements on more than one interferometer baseline, necessitating, for example, more than two satellites for a space-based detector or two interferometer arms for a ground-based detector. We describe a new detection strategy based on recent advances in optical atomic clocks and atom interferometry which can operate at long baselines and which is immune to laser frequency noise. Laser frequency noise is suppressed because the signal arises strictly from the light propagation time between two ensembles of atoms. This new class of sensor allows sensitive gravitational wave detection with only a single baseline. This approach also has practical applications in, for example, the development of ultrasensitive gravimeters and gravity gradiometers.

    View details for PubMedID 23679702

  • Ultrafast microfocus x-ray source based on a femtosecond laser-triggered tip ANNALEN DER PHYSIK Foreman, S. M., Kealhofer, C., Skulason, G. E., Klopfer, B. B., Kasevich, M. A. 2013; 525 (1-2): L19-L22
  • Generation of 43 W of quasi-continuous 780 nm laser light via high-efficiency, single-pass frequency doubling in periodically poled lithium niobate crystals OPTICS LETTERS Chiow, S., Kovachy, T., Hogan, J. M., Kasevich, M. A. 2012; 37 (18): 3861-3863

    Abstract

    We demonstrate high-efficiency frequency doubling of the combined output of two 1560 nm 30 W fiber amplifiers via single pass through periodically poled lithium niobate (PPLN) crystals. The temporal profile of the 780 nm output is controlled by adjusting the relative phase between the seeds of the amplifiers. We obtain a peak power of 34 W of 780 nm light by passing the combined output through one PPLN crystal, and a peak power of 43 W by passing through two cascading PPLN crystals. This source provides high optical power, excellent beam quality and spectral purity, and agile frequency and amplitude control in a simple and compact setup, which is ideal for applications such as atom optics using Rb atoms.

    View details for Web of Science ID 000309046300041

    View details for PubMedID 23041884

  • Adiabatic-rapid-passage multiphoton Bragg atom optics PHYSICAL REVIEW A Kovachy, T., Chiow, S., Kasevich, M. A. 2012; 86 (1)
  • Ultrafast laser-triggered emission from hafnium carbide tips PHYSICAL REVIEW B Kealhofer, C., Foreman, S. M., Gerlich, S., Kasevich, M. A. 2012; 86 (3)
  • A high-performance magnetic shield with large length-to-diameter ratio REVIEW OF SCIENTIFIC INSTRUMENTS Dickerson, S., Hogan, J. M., Johnson, D. M., Kovachy, T., Sugarbaker, A., Chiow, S., Kasevich, M. A. 2012; 83 (6)

    Abstract

    We have demonstrated a 100-fold improvement in the magnetic field uniformity on the axis of a large aspect ratio, cylindrical, mumetal magnetic shield by reducing discontinuities in the material of the shield through the welding and re-annealing of a segmented shield. The three-layer shield reduces Earth's magnetic field along an 8 m region to 420 μG (rms) in the axial direction, and 460 and 730 μG (rms) in the two transverse directions. Each cylindrical shield is a continuous welded tube which has been annealed after manufacture and degaussed in the apparatus. We present both experiments and finite element analysis that show the importance of uniform shield material for large aspect ratio shields, favoring a welded design over a segmented design. In addition, we present finite element results demonstrating the smoothing of spatial variations in the applied magnetic field by cylindrical magnetic shields. Such homogenization is a potentially useful feature for precision atom interferometric measurements.

    View details for DOI 10.1063/1.4720943

    View details for Web of Science ID 000305833100056

    View details for PubMedID 22755663

  • Atom Interferometric Gravity Sensor System IEEE/ION Position Location and Navigation Symposium (PLANS) Brown, D., Mauser, L., Young, B., Kasevich, M., Rice, H. F., Benischek, V. IEEE. 2012: 30–37
  • Absolute Geodetic Rotation Measurement Using Atom Interferometry PHYSICAL REVIEW LETTERS Stockton, J. K., Takase, K., Kasevich, M. A. 2011; 107 (13)

    Abstract

    We demonstrate a cold-atom interferometer gyroscope which overcomes accuracy and dynamic range limitations of previous atom interferometer gyroscopes. We show how the instrument can be used for precise determination of latitude, azimuth (true north), and Earth's rotation rate. Spurious noise terms related to multiple-path interferences are suppressed by employing a novel time-skewed pulse sequence. Extended versions of this instrument appear capable of meeting the stringent requirements for inertial navigation, geodetic applications of Earth's rotation rate determination, and tests of general relativity.

    View details for DOI 10.1103/PhysRevLett.107.133001

    View details for Web of Science ID 000295137200003

    View details for PubMedID 22026848

  • 102(h)over-bark Large Area Atom Interferometers PHYSICAL REVIEW LETTERS Chiow, S., Kovachy, T., Chien, H., Kasevich, M. A. 2011; 107 (13)

    Abstract

    We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta (102ℏk). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves.

    View details for DOI 10.1103/PhysRevLett.107.130403

    View details for Web of Science ID 000295005200003

    View details for PubMedID 22026831

  • Raman Lasing with a Cold Atom Gain Medium in a High-Finesse Optical Cavity PHYSICAL REVIEW LETTERS Vrijsen, G., Hosten, O., Lee, J., Bernon, S., Kasevich, M. A. 2011; 107 (6)

    Abstract

    We demonstrate a Raman laser using cold (87)Rb atoms as the gain medium in a high-finesse optical cavity. We observe robust continuous wave lasing in the atypical regime where single atoms can considerably affect the cavity field. Consequently, we discover unusual lasing threshold behavior in the system causing jumps in lasing power, and propose a model to explain the effect. We also measure the intermode laser linewidth, and observe values as low as 80 Hz. The tunable gain properties of this laser suggest multiple directions for future research.

    View details for DOI 10.1103/PhysRevLett.107.063904

    View details for PubMedID 21902327

  • Reply to "Comment on 'Atomic gravitational wave interferometric sensor'" PHYSICAL REVIEW D Dimopoulos, S., Graham, P. W., Hogan, J. M., Kasevich, M. A., Rajendran, S. 2011; 84 (2)
  • An atomic gravitational wave interferometric sensor in low earth orbit (AGIS-LEO) GENERAL RELATIVITY AND GRAVITATION Hogan, J. M., Johnson, D. M., Dickerson, S., Kovachy, T., Sugarbaker, A., Chiow, S., Graham, P. W., Kasevich, M. A., Saif, B., Rajendran, S., Bouyer, P., Seery, B. D., Feinberg, L., Keski-Kuha, R. 2011; 43 (7): 1953-2009
  • Microwave Guiding of Electrons on a Chip PHYSICAL REVIEW LETTERS Hoffrogge, J., Froehlich, R., Kasevich, M. A., Hommelhoff, P. 2011; 106 (19)

    Abstract

    We demonstrate the transverse confinement and guiding of a low energy electron beam of several electron volts in a miniaturized linear quadrupole guide. The guiding potential is generated by applying a microwave voltage to electrodes fabricated on a planar substrate, which allows the potential landscape to be precisely shaped on a microscopic scale. We realize transverse trapping frequencies of 100 MHz and guide electrons along a circular section of 37 mm length. A detailed characterization of the guiding properties in terms of potential depth and dynamic stability is given. This new technique of electron guiding promises various applications in guided matter-wave experiments such as electron interferometry.

    View details for DOI 10.1103/PhysRevLett.106.193001

    View details for Web of Science ID 000290383500006

    View details for PubMedID 21668147

  • Precision angle sensor using an optical lever inside a Sagnac interferometer OPTICS LETTERS Hogan, J. M., Hammer, J., Chiow, S., Dickerson, S., Johnson, D. M., Kovachy, T., Sugarbaker, A., Kasevich, M. A. 2011; 36 (9): 1698-1700

    Abstract

    We built an ultra-low-noise angle sensor by combining a folded optical lever and a Sagnac interferometer. The instrument has a measured noise floor of 1.3 prad/√Hz at 2.4 kHz. We achieve this record angle sensitivity using a proof-of-concept apparatus with a conservative N=11 bounces in the optical lever. This technique could be extended to reach subpicoradian/√Hz sensitivities with an optimized design.

    View details for Web of Science ID 000290037300058

    View details for PubMedID 21540973

  • Picosecond Optical Switching Using RF Nonlinear Transmission Lines JOURNAL OF LIGHTWAVE TECHNOLOGY Johnson, D. M., Hogan, J. M., Chiow, S., Kasevich, M. A. 2011; 29 (5): 666-669
  • Optical lattices as waveguides and beam splitters for atom interferometry: An analytical treatment and proposal of applications PHYSICAL REVIEW A Kovachy, T., Hogan, J. M., Johnson, D. M., Kasevich, M. A. 2010; 82 (1)
  • Broadband optical serrodyne frequency shifting OPTICS LETTERS Johnson, D. M., Hogan, J. M., Chiow, S., Kasevich, M. A. 2010; 35 (5): 745-747

    Abstract

    We demonstrate serrodyne frequency shifting of light from 200 MHz to 1.2 GHz with an efficiency of better than 60%. The frequency shift is imparted by an electro-optic phase modulator driven by a high-frequency high-fidelity sawtooth waveform that is passively generated by a commercially available nonlinear transmission line. We also implement a push-pull configuration using two serrodyne-driven phase modulators, allowing for continuous tuning between -1.6 GHz and +1.6 GHz. Compared with competing technologies, this technique is simple and robust, and it offers the largest available tuning range in this frequency band.

    View details for Web of Science ID 000275826700044

    View details for PubMedID 20195339

  • Atom Interferometric Navigation Sensors 2010 IEEE Sensors Conference Kasevich, M. IEEE. 2010: 15–16
  • Phase-Slip Interferometry for Precision Force Measurements PHYSICAL REVIEW LETTERS Tuchman, A. K., Kasevich, M. A. 2009; 103 (13)

    Abstract

    We demonstrate a novel atom interferometric force sensor based on phase slips in the dynamic evolution of a squeezed-state array of degenerate ;{87}Rb atoms confined in a one-dimensional optical lattice. The truncated Wigner approximation is used to model our observations.

    View details for DOI 10.1103/PhysRevLett.103.130403

    View details for Web of Science ID 000270241100003

    View details for PubMedID 19905495

  • Gravitational wave detection with atom interferometry PHYSICS LETTERS B Dimopoulos, S., Graham, P. W., Hogan, J. M., Kasevich, M. A., Rajendran, S. 2009; 678 (1): 37-40
  • Reaching the resolved tunnel regime for a femtosecond oscillator driven field emission electron source LASER PHYSICS Hommelhoff, P., Kealhofer, C., Kasevich, M. A. 2009; 19 (4): 736-738
  • Extreme localization of electrons in space and time 51st International Field Emission Symposium Hommelhoff, P., Kealhofer, C., Aghajani-Talesh, A., Sortais, Y. R., Foreman, S. M., Kasevich, M. A. ELSEVIER SCIENCE BV. 2009: 423–29

    Abstract

    Electron emission from sharp metal tips can take place on sub-femtosecond time scales if the emission is driven by few cycle femtosecond laser pulses. Here we outline the experimental prerequisites in detail, discuss emission regimes and relate them to recent experiments in the gas phase (attosecond physics). We present a process that leads to single atom tip emitters that are stable under laser illumination and conclude with a discussion of how to achieve short electron pulses at a target.

    View details for DOI 10.1016/j.ultramic.2008.10.021

    View details for Web of Science ID 000265345500011

    View details for PubMedID 19117677

  • Low-noise simultaneous fluorescence detection of two atomic states OPTICS LETTERS Biedermann, G. W., Wu, X., Deslauriers, L., Takase, K., Kasevich, M. A. 2009; 34 (3): 347-349

    Abstract

    We demonstrate a new simultaneous normalized detection technique for fluorescence detection of ultracold atoms in a superposition of ground-state hyperfine levels. Using this technique we observe atom shot-noise limited detection signal-to-noise ratios in excess of 7800:1 per shot and 14400:1 in 1 s.

    View details for Web of Science ID 000263755800042

    View details for PubMedID 19183654

  • PRECISION NAVIGATION SENSORS BASED ON COLD ATOMS AAS/AIAA 19th Space Flight Mechanics Meeting Kasevich, M. A. UNIVELT INC. 2009: 1179–1188
  • Ultrafast Laser-Induced Electron Emission from Field Emission Tips 16th International Conference on Ultrafast Phenomena Kealhofer, C., Foreman, S. M., Hommelhoff, P., Kasevich, M. A. SPRINGER-VERLAG BERLIN. 2009: 702–704
  • Atomic gravitational wave interferometric sensor PHYSICAL REVIEW D Dimopoulos, S., Graham, P. W., Hogan, J. M., Kasevich, M. A., Rajendran, S. 2008; 78 (12)
  • Backaction noise produced via cavity-aided nondemolition measurement of an atomic clock state PHYSICAL REVIEW A Teper, I., Vrijsen, G., Lee, J., Kasevich, M. A. 2008; 78 (5)
  • General relativistic effects in atom interferometry PHYSICAL REVIEW D Dimopoulos, S., Graham, P. W., Hogan, J. M., Kasevich, M. A. 2008; 78 (4)
  • How to test atom and neutron neutrality with atom interferometry PHYSICAL REVIEW LETTERS Arvanitaki, A., Dimopoulos, S., Geraci, A. A., Hogan, J., Kasevich, M. 2008; 100 (12)

    Abstract

    We propose an atom-interferometry experiment based on the scalar Aharonov-Bohm effect which detects an atom charge at the 10{-28}e level, and improves the current laboratory limits by 8 orders of magnitude. This setup independently probes neutron charges down to 10{-28}e, 7 orders of magnitude below current bounds.

    View details for DOI 10.1103/PhysRevLett.100.120407

    View details for Web of Science ID 000254473800007

    View details for PubMedID 18517846

  • Space-based research in fundamental physics and quantum technologies International Workshop From Quantum to Cosmos - Fundamental Physics Research in Space Turyshev, S. G., Israelsson, U. E., Shao, M., Yu, N., Kusenko, A., Wright, E. L., Everitt, C. W., Kasevich, M., Lipa, J. A., Mester, J. C., Reasenberg, R. D., Walsworth, R. L., Ashby, N., Gould, H., Paik, H. J. WORLD SCIENTIFIC PUBL CO PTE LTD. 2007: 1879–1925
  • DETECTING LORENTZ INVARIANCE VIOLATIONS IN THE 10(-20) RANGE INTERNATIONAL JOURNAL OF MODERN PHYSICS D Lipa, J. A., Wang, S., NISSEN, J., Kasevich, M., Mester, J. 2007; 16 (12B): 2393-2398
  • High-power pulsed-current-mode operation of an overdriven tapered amplifier OPTICS LETTERS Takase, K., Stockton, J. K., Kasevich, M. A. 2007; 32 (17): 2617-2619

    Abstract

    We experimentally investigate the performance of a commercial tapered amplifier diode operating in a pulsed-current mode with a peak current that is significantly higher than the specified maximum continuous current. For a tapered amplifier rated at 500 mW of continuous power, we demonstrate 2.6 W of peak optical output power with 15 mW of injection light for 200 micros, 7 A current pulses. Different failure mechanisms for the tapered amplifier, including thermal and optical damage, are identified under these conditions.

    View details for Web of Science ID 000249908000052

    View details for PubMedID 17767324

  • Bayesian estimation of differential interferometer phase PHYSICAL REVIEW A Stockton, J. K., Wu, X., Kasevich, M. A. 2007; 76 (3)
  • Multiple frequency modulation for low-light atom measurements in an optical cavity OPTICS LETTERS Long, R., Tuchman, A. K., Kasevich, M. A. 2007; 32 (17): 2502-2504

    Abstract

    We present a frequency modulation scheme to detect atoms dispersively in a high-finesse optical cavity at low-light levels with immunity to cavity length fluctuations. We use multiple cavity resonances to provide common mode noise rejection, keeping the high intensity carrier off-resonant from all cavity modes. The method has applications in atomic squeezed state generation and quantum metrology.

    View details for Web of Science ID 000249908000013

    View details for PubMedID 17767285

  • Testing general relativity with atom interferometry PHYSICAL REVIEW LETTERS Dimopoulos, S., Graham, P. W., Hogan, J. M., Kasevich, M. A. 2007; 98 (11)

    Abstract

    The unprecedented precision of atom interferometry will soon lead to laboratory tests of general relativity to levels that will rival or exceed those reached by astrophysical observations. We propose such an experiment that will initially test the equivalence principle to 1 part in 10(15) (300 times better than the current limit), and 1 part in 10(17) in the future. It will also probe general relativistic effects - such as the nonlinear three-graviton coupling, the gravity of an atom's kinetic energy, and the falling of light - to several decimals. In contrast with astrophysical observations, laboratory tests can isolate these effects via their different functional dependence on experimental variables.

    View details for DOI 10.1103/PhysRevLett.98.111102

    View details for Web of Science ID 000244959300014

    View details for PubMedID 17501039

  • Extended coherence time with atom-number squeezed states PHYSICAL REVIEW LETTERS Li, W., Tuchman, A. K., Chien, H., Kasevich, M. A. 2007; 98 (4)

    Abstract

    Coherence properties of Bose-Einstein condensates offer the potential for improved interferometric phase contrast. However, decoherence effects due to the mean-field interaction shorten the coherence time, thus limiting potential sensitivity. In this work, we demonstrate increased coherence times with number squeezed states in an optical lattice using the decay of Bloch oscillations to probe the coherence time. We extend coherence times by a factor of 2 over those expected with coherent state Bose-Einstein condensate interferometry. We observe quantitative agreement with theory both for the degree of initial number squeezing as well as for prolonged coherence times.

    View details for DOI 10.1103/PhysRevLett.98.040402

    View details for Web of Science ID 000243789700002

    View details for PubMedID 17358746

  • Atom interferometer measurement of the newtonian constant of gravity SCIENCE Fixler, J. B., Foster, G. T., McGuirk, J. M., Kasevich, M. A. 2007; 315 (5808): 74-77

    Abstract

    We measured the Newtonian constant of gravity, G, using a gravity gradiometer based on atom interferometry. The gradiometer measures the differential acceleration of two samples of laser-cooled Cs atoms. The change in gravitational field along one dimension is measured when a well-characterized Pb mass is displaced. Here, we report a value of G = 6.693 x 10(-11) cubic meters per kilogram second squared, with a standard error of the mean of +/-0.027 x 10(-11) and a systematic error of +/-0.021 x 10(-11) cubic meters per kilogram second squared. The possibility that unknown systematic errors still exist in traditional measurements makes it important to measure G with independent methods.

    View details for DOI 10.1126/science.1135459

    View details for Web of Science ID 000243259100037

    View details for PubMedID 17204644

  • A spatially and temporally localized sub-laser cycle electron source 15th International Conference on Ultrafast Phenomena Hommelhoff, P., Kealhofer, C., Kasevich, M. A. SPRINGER-VERLAG BERLIN. 2007: 746–748
  • Reaching Li-7 quantum degeneracy with a minitrap PHYSICAL REVIEW A Wang, R., Liu, M., Minardi, F., Kasevich, M. 2007; 75 (1)
  • Long-term stability of an area-reversible atom-interferometer sagnac gyroscope PHYSICAL REVIEW LETTERS Durfee, D. S., Shaham, Y. K., Kasevich, M. A. 2006; 97 (24)

    Abstract

    We report the first demonstration of a matter-wave interference gyroscope that meets both the short-term noise and long-term stability requirements for high accuracy navigation. This performance level resulted from implementation of a novel technique to precisely reverse the input axis of the gyroscope.

    View details for DOI 10.1103/PhysRevLet.97.240801

    View details for Web of Science ID 000242888700009

    View details for PubMedID 17280264

  • Ultrafast electron pulses from a tungsten tip triggered by low-power femtosecond laser pulses PHYSICAL REVIEW LETTERS Hommelhoff, P., Kealhofer, C., Kasevich, M. A. 2006; 97 (24)

    Abstract

    We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8-fs low-power laser pulses. This process is nonlinear in the laser electric field, and the nonlinearity can be tuned via the dc voltage applied to the tip. Numerical simulations of this system show that electron emission takes place within less than one optical period of the exciting laser pulse, so that an 8 fs 800 nm laser pulse is capable of producing a single electron pulse of less than 1 fs duration. Furthermore, we find that the carrier-envelope phase dependence of the emission process is smaller than 0.1% for an 8 fs pulse but is steeply increasing with decreasing laser pulse duration.

    View details for DOI 10.1103/PhysRevLett.97.247402

    View details for Web of Science ID 000242888700067

    View details for PubMedID 17280322

  • Localization and anomalous transport in a 1D soft boson optical lattice NEW JOURNAL OF PHYSICS Tuchman, A. K., Li, W., Chien, H., Dettmer, S., Kasevich, M. A. 2006; 8
  • Nonequilibrium coherence dynamics of a soft boson lattice PHYSICAL REVIEW A Tuchman, A. K., Orzel, C., Polkovnikov, A., Kasevich, M. A. 2006; 74 (5)
  • Normal-mode splitting with large collective cooperativity PHYSICAL REVIEW A Tuchman, A. K., Long, R., Vrijsen, G., Boudet, J., Lee, J., Kasevich, M. A. 2006; 74 (5)
  • Special issue: "Quantum mechanics for space application: From quantum optics to atom optics and general relativity" APPLIED PHYSICS B-LASERS AND OPTICS Kasevich, M., Salomon, C. 2006; 84 (4): 543-544
  • High-order inertial phase shifts for time-domain atom interferometers 11th Congress of the International-Association-of-Biomedical-Gerontology Bongs, K., Launay, R., Kasevich, M. A. SPRINGER. 2006: 599–602
  • Atom interferometer as a selective sensor of rotation or gravity PHYSICAL REVIEW A Dubetsky, B., Kasevich, M. A. 2006; 74 (2)
  • Field emission tip as a nanometer source of free electron femtosecond pulses PHYSICAL REVIEW LETTERS Hommelhoff, P., Sortais, Y., Aghajani-Talesh, A., Kasevich, M. A. 2006; 96 (7)

    Abstract

    We report a source of free electron pulses based on a field emission tip irradiated by a low-power femtosecond laser. The electron pulses are shorter than 70 fs and originate from a tip with an emission area diameter down to 2 nm. Depending on the operating regime we observe either photofield emission or optical field emission with up to 200 electrons per pulse at a repetition rate of 1 GHz. This pulsed electron emitter, triggered by a femtosecond oscillator, could serve as an efficient source for time-resolved electron interferometry, for time-resolved nanometric imaging and for synchrotrons.

    View details for DOI 10.1103/PhysRevLett.96.077401

    View details for Web of Science ID 000235554100078

    View details for PubMedID 16606139

  • Femtosecond laser meets field emission tip - a sensor for the carrier envelope phase? IEEE International Frequency Control Symposium and Exposition Hommelhoff, P., Kealhofer, C., Kasevich, M. A. IEEE. 2006: 470–474
  • Coherence with atoms SCIENCE Kasevich, M. A. 2002; 298 (5597): 1363-1368

    Abstract

    The past decade has seen dramatic progress in our ability to manipulate and coherently control the motion of atoms. This progress has both fundamental and applied importance. On the one hand, recent experiments are providing new perspectives for the study of quantum phase transitions and highly entangled quantum states. On the other hand, this exquisite control offers the prospect of a new generation of force sensors of unprecedented sensitivity and accuracy.

    View details for Web of Science ID 000179223100038

    View details for PubMedID 12434050

  • Heisenberg-limited spectroscopy with degenerate Bose-Einstein gases PHYSICAL REVIEW A Bouyer, P., Kasevich, M. A. 1997; 56 (2): R1083-R1086
  • Detector for spatial and temporal imaging of single photons REVIEW OF SCIENTIFIC INSTRUMENTS Sinclair, A. G., Kasevich, M. A. 1997; 68 (4): 1657-1660
  • Precision rotation measurements with an atom interferometer gyroscope PHYSICAL REVIEW LETTERS Gustavson, T. L., Bouyer, P., Kasevich, M. A. 1997; 78 (11): 2046-2049
  • Microwave signal generation with optical injection locking OPTICS LETTERS Bouyer, P., Gustavson, T. L., Haritos, K. G., Kasevich, M. A. 1996; 21 (18): 1502-1504

    Abstract

    Two single-mode laser diodes have been injection locked to the +1 and -1 diffracted orders of a 4.6-GHz acousto-optical modulator. The measured locking bandwidth was 3 GHz for a locking gain of 35 dB. The microwave signal at 9.2 GHz had a measured linewidth of less than a few hertz. We used this system to drive stimulated Raman transitions between the cesium ground-state hyperfine levels. We observed Ramsey fringes and used them to characterize the microwave signal phase noise.

    View details for Web of Science ID A1996VG59400030

    View details for PubMedID 19881705

  • Atom trapping in nondissipative optical lattices PHYSICAL REVIEW A Anderson, B. P., Gustavson, T. L., Kasevich, M. A. 1996; 53 (6): R3727-R3730
  • Nonlinear-optical properties of a noninteracting Bose gas OPTICS LETTERS Kasevich, M. A., Harris, S. E. 1996; 21 (9): 677-679

    Abstract

    We show that the characteristic Rabi frequency and nonlinear susceptibility of atoms in a dilute Bose gas remain unchanged by the process of condensation. We neglect the effects of atomic dipole-dipole interactions and spontaneous emission.

    View details for Web of Science ID A1996UG32200019

    View details for PubMedID 19876122

  • Raman cooling of atoms in an optical dipole trap PHYSICAL REVIEW LETTERS Lee, H. J., Adams, C. S., Kasevich, M., Chu, S. 1996; 76 (15): 2658-2661
  • INTERACTION-FREE MEASUREMENT PHYSICAL REVIEW LETTERS Kwiat, P., Weinfurter, H., Herzog, T., Zeilinger, A., Kasevich, M. A. 1995; 74 (24): 4763-4766
  • EVAPORATIVE COOLING IN A CROSSED DIPOLE TRAP PHYSICAL REVIEW LETTERS Adams, C. S., Lee, H. J., Davidson, N., Kasevich, M., Chu, S. 1995; 74 (18): 3577-3580
  • LONG ATOMIC COHERENCE TIMES IN AN OPTICAL DIPOLE TRAP PHYSICAL REVIEW LETTERS Davidson, N., Lee, H. J., Adams, C. S., Kasevich, M., Chu, S. 1995; 74 (8): 1311-1314
  • DIPOLE TRAPPING, COOLING IN TRAPS, AND LONG COHERENCE TIMES 14th International Conference on Atomic Physics (ICAP-14) Lee, H. J., Adams, C., Davidson, N., Young, B., Weitz, M., Kasevich, M., Chu, S. AMER INST PHYSICS. 1995: 258–75
  • EXPERIMENTAL REALIZATION OF INTERACTION-FREE MEASUREMENTS Conference on Fundamental Problems in Quantum Theory, A Conference held in Honor of Professor John A. Wheeler Kwiat, P., Weinfurter, H., Herzog, T., Zeilinger, A., Kasevich, M. NEW YORK ACAD SCIENCES. 1995: 383–393
  • ENHANCED LOADING OF A MAGNETOOPTIC TRAP FROM AN ATOMIC-BEAM PHYSICAL REVIEW A Anderson, B. P., Kasevich, M. A. 1994; 50 (5): R3581-R3584
  • RAMAN COOLING OF ATOMS IN 2-DIMENSIONS AND 3-DIMENSIONS PHYSICAL REVIEW LETTERS Davidson, N., Lee, H. J., Kasevich, M., Chu, S. 1994; 72 (20): 3158-3161
  • LASER COOLING BELOW A PHOTON RECOIL WITH 3-LEVEL ATOMS PHYSICAL REVIEW LETTERS Kasevich, M., Chu, S. 1992; 69 (12): 1741-1744
  • MEASUREMENT OF THE GRAVITATIONAL ACCELERATION OF AN ATOM WITH A LIGHT-PULSE ATOM INTERFEROMETER APPLIED PHYSICS B-PHOTOPHYSICS AND LASER CHEMISTRY Kasevich, M., Chu, S. 1992; 54 (5): 321-332
  • MEASUREMENT OF THE ACCELERATION DUE TO GRAVITY WITH AN ATOMIC INTERFEROMETER WORKSHOP ON THE FOUNDATIONS OF QUANTUM MECHANICS Kasevich, M., Chu, S. WORLD SCIENTIFIC PUBL CO PTE LTD. 1992: 47–54
  • THEORETICAL-ANALYSIS OF VELOCITY-SELECTIVE RAMAN TRANSITIONS PHYSICAL REVIEW A Moler, K., Weiss, D. S., Kasevich, M., Chu, S. 1992; 45 (1): 342-348
  • ATOMIC INTERFEROMETRY USING STIMULATED RAMAN TRANSITIONS PHYSICAL REVIEW LETTERS Kasevich, M., Chu, S. 1991; 67 (2): 181-184
  • ATOMIC VELOCITY SELECTION USING STIMULATED RAMAN TRANSITIONS PHYSICAL REVIEW LETTERS Kasevich, M., Weiss, D. S., Riis, E., Moler, K., Kasapi, S., Chu, S. 1991; 66 (18): 2297-2300
  • NORMAL-INCIDENCE REFLECTION OF SLOW ATOMS FROM AN OPTICAL EVANESCENT WAVE OPTICS LETTERS Kasevich, M. A., Weiss, D. S., Chu, S. 1990; 15 (11): 607-609

    View details for Web of Science ID A1990DG12400005

    View details for PubMedID 19768022

  • RF SPECTROSCOPY IN AN ATOMIC FOUNTAIN PHYSICAL REVIEW LETTERS Kasevich, M. A., Riis, E., Chu, S., DeVoe, R. G. 1989; 63 (6): 612-616