Professional Education


  • Master of Science, Georgia Institute of Technology, Electrical Engineering (2002)
  • Ingeniero, Universidad De Los Andes, Electrical Engineering (1998)
  • Doctor of Philosophy, Stanford University, EE-PHD (2013)

Stanford Advisors


All Publications


  • Nonclassical higher-order photon correlations with a quantum dot strongly coupled to a photonic-crystal nanocavity PHYSICAL REVIEW A Rundquist, A., Bajcsy, M., Majumdar, A., Sarmiento, T., Fischer, K., Lagoudakis, K. G., Buckley, S., Piggott, A. Y., Vuckovic, J. 2014; 90 (2)
  • Photo-oxidative tuning of individual and coupled GaAs photonic crystal cavities OPTICS EXPRESS Piggott, A. Y., Lagoudakis, K. G., Sarmiento, T., Bajcsy, M., Shambat, G., Vuckovic, J. 2014; 22 (12): 15017-15023
  • Electrically driven subwavelength optical nanocircuits NATURE PHOTONICS Huang, K. C., Seo, M., Sarmiento, T., Huo, Y., Harris, J. S., Brongersma, M. L. 2014; 8 (3): 244-249
  • Time-resolved photoluminescence studies of annealed 1.3-µm GaInNAsSb quantum wells. Nanoscale research letters Baranowski, M., Kudrawiec, R., Syperek, M., Misiewicz, J., Sarmiento, T., Harris, J. S. 2014; 9 (1): 81-?

    Abstract

    Time-resolved photoluminescence (PL) was applied to study the dynamics of carrier recombination in GaInNAsSb quantum wells (QWs) emitting near 1.3 μm and annealed at various temperatures. It was observed that the annealing temperature has a strong influence on the PL decay time, and hence, it influences the optical quality of GaInNAsSb QWs. At low temperatures, the PL decay time exhibits energy dependence (i.e., the decay times change for different energies of emitted photons), which can be explained by the presence of localized states. This energy dependence of PL decay times was fitted by a phenomenological formula, and the average value of E0, which describes the energy distribution of localized states, was extracted from this fit and found to be smallest (E0 = 6 meV) for the QW annealed at 700°C. In addition, the value of PL decay time at the peak energy was compared for all samples. The longest PL decay time (600 ps) was observed for the sample annealed at 700°C. It means that based on the PL dynamics, the optimal annealing temperature for this QW is approximately 700°C.

    View details for DOI 10.1186/1556-276X-9-81

    View details for PubMedID 24533740

    View details for PubMedCentralID PMC3942105

  • Deterministically charged quantum dots in photonic crystal nanoresonators for efficient spin-photon interfaces NEW JOURNAL OF PHYSICS Lagoudakis, K. G., Fischer, K., Sarmiento, T., Majumdar, A., Rundquist, A., Lu, J., Bajcsy, M., Vuckovic, J. 2013; 15
  • Single-cell photonic nanocavity probes. Nano letters Shambat, G., Kothapalli, S., Provine, J., Sarmiento, T., Harris, J., Gambhir, S. S., Vuckovic, J. 2013; 13 (11): 4999-5005

    Abstract

    In this report, we demonstrate for the first time photonic nanocavities operating inside single biological cells. Here we develop a nanobeam photonic crystal (PC) cavity as an advanced cellular nanoprobe, active in nature, and configurable to provide a multitude of actions for both intracellular sensing and control. Our semiconductor nanocavity probes emit photoluminescence (PL) from embedded quantum dots (QD) and sustain high quality resonant photonic modes inside cells. The probes are shown to be minimally cytotoxic to cells from viability studies, and the beams can be loaded in cells and tracked for days at a time, with cells undergoing regular division with the beams. We present in vitro label-free protein sensing with our probes to detect streptavidin as a path towards real-time biomarker and biomolecule detection inside single cells. The results of this work will enable new areas of research merging the strengths of photonic nanocavities with fundamental cell biology.

    View details for DOI 10.1021/nl304602d

    View details for PubMedID 23387382

  • Enhancement of photoluminescence from GaInNAsSb quantum wells upon annealing: improvement of material quality and carrier collection by the quantum well JOURNAL OF PHYSICS-CONDENSED MATTER Baranowski, M., Kudrawiec, R., Latkowska, M., Syperek, M., Misiewicz, J., Sarmiento, T., Harris, J. S. 2013; 25 (6)

    Abstract

    In this study we apply time resolved photoluminescence and contactless electroreflectance to study the carrier collection efficiency of a GaInNAsSb/GaAs quantum well (QW). We show that the enhancement of photoluminescence from GaInNAsSb quantum wells annealed at different temperatures originates not only from (i) the improvement of the optical quality of the GaInNAsSb material (i.e., removal of point defects, which are the source of nonradiative recombination) but it is also affected by (ii) the improvement of carrier collection by the QW region. The total PL efficiency is the product of these two factors, for which the optimal annealing temperatures are found to be ~700 °C and ~760 °C, respectively, whereas the optimal annealing temperature for the integrated PL intensity is found to be between the two temperatures and equals ~720 °C. We connect the variation of the carrier collection efficiency with the modification of the band bending conditions in the investigated structure due to the Fermi level shift in the GaInNAsSb layer after annealing.

    View details for DOI 10.1088/0953-8984/25/6/065801

    View details for Web of Science ID 000313950600015

    View details for PubMedID 23306016

  • Photon-enhanced thermionic emission from heterostructures with low interface recombination. Nature communications Schwede, J. W., Sarmiento, T., NARASIMHAN, V. K., Rosenthal, S. J., Riley, D. C., Schmitt, F., Bargatin, I., Sahasrabuddhe, K., Howe, R. T., Harris, J. S., Melosh, N. A., Shen, Z. 2013; 4: 1576-?

    Abstract

    Photon-enhanced thermionic emission is a method of solar-energy conversion that promises to combine photon and thermal processes into a single mechanism, overcoming fundamental limits on the efficiency of photovoltaic cells. Photon-enhanced thermionic emission relies on vacuum emission of photoexcited electrons that are in thermal equilibrium with a semiconductor lattice, avoiding challenging non-equilibrium requirements and exotic material properties. However, although previous work demonstrated the photon-enhanced thermionic emission effect, efficiency has until now remained very low. Here we describe electron-emission measurements on a GaAs/AlGaAs heterostructure that introduces an internal interface, decoupling the basic physics of photon-enhanced thermionic emission from the vacuum emission process. Quantum efficiencies are dramatically higher than in previous experiments because of low interface recombination and are projected to increase another order of magnitude with more stable, low work-function coatings. The results highlight the effectiveness of the photon-enhanced thermionic emission process and demonstrate that efficient photon-enhanced thermionic emission is achievable, a key step towards realistic photon-enhanced thermionic emission based energy conversion.

    View details for DOI 10.1038/ncomms2577

    View details for PubMedID 23481384

  • Photon-enhanced thermionic emission from heterostructures with low interface recombination. Nature communications Schwede, J. W., Sarmiento, T., NARASIMHAN, V. K., Rosenthal, S. J., Riley, D. C., Schmitt, F., Bargatin, I., Sahasrabuddhe, K., Howe, R. T., Harris, J. S., Melosh, N. A., Shen, Z. 2013; 4: 1576-?

    View details for DOI 10.1038/ncomms2577

    View details for PubMedID 23481384

  • Electrically controlled photonic crystal nanocavity sources and modulators IEEE-Photonics-Society Summer Topical Meeting Petykiewicz, J., Shambat, G., Ellis, B., Sarmiento, T., Piggott, A., Vuckovic, J. IEEE. 2013: 38–39
  • Electrically Driven Photonic Crystal Nanocavity Devices IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS Shambat, G., Ellis, B., Petykiewicz, J., Mayer, M. A., Majumdar, A., Sarmiento, T., Harris, J. S., Haller, E. E., Vuckovic, J. 2012; 18 (6): 1700-1710
  • Antenna electrodes for controlling electroluminescence NATURE COMMUNICATIONS Huang, K. C., Seo, M., Huo, Y., Sarmiento, T., Harris, J. S., Brongersma, M. L. 2012; 3

    Abstract

    Optical antennas can control the emission from quantum emitters by modifying the local density of optical states via the Purcell effect. A variety of nanometallic antennas have been implemented to enhance and control key photoluminescence properties, such as the decay rate, directionality and polarization. However, their implementation in active devices has been hampered by the need to precisely place emitters near an antenna and to efficiently excite them electrically. Here we illustrate a design methodology for antenna electrodes that for the first time facilitates simultaneous operation as electrodes for current injection and as antennas capable of optically manipulating the electroluminescence. We show that by confining the electrically excited carriers to the vicinity of antenna electrodes and maximizing the optical coupling of the emission to a single, well-defined antenna mode, their electroluminescence can be effectively controlled. This work spurs the development of densely integrated, electrically driven light sources with tailored emission properties.

    View details for DOI 10.1038/ncomms1985

    View details for Web of Science ID 000308801100021

    View details for PubMedID 22893129

  • A photonic crystal cavity-optical fiber tip nanoparticle sensor for biomedical applications APPLIED PHYSICS LETTERS Shambat, G., Kothapalli, S. R., Khurana, A., Provine, J., Sarmiento, T., Cheng, K., Cheng, Z., Harris, J., Daldrup-Link, H., Gambhir, S. S., Vuckovic, J. 2012; 100 (21)

    View details for DOI 10.1063/1.4719520

    View details for Web of Science ID 000304489900085

  • Ultrafast Direct Modulation of a Single-Mode Photonic Crystal Nanocavity Light-Emitting Diode Conference on Lasers and Electro-Optics (CLEO) Shambat, G., Ellis, B., Majumdar, A., Petykiewicz, J., Mayer, M., Sarmiento, T., Harris, J., Haller, E., Vuckovic, J. IEEE. 2012
  • Electrically driven photonic crystal nanocavity lasers, LEDs, and modulators Conference on Novel In-Plane Semiconductor Lasers XI Shambat, G., Ellis, B., Mayer, M., Majumdar, A., Petykiewicz, J., Sarmiento, T., Harris, J., Haller, E. E., Vuckovic, J. SPIE-INT SOC OPTICAL ENGINEERING. 2012

    View details for DOI 10.1117/12.907432

    View details for Web of Science ID 000305332300003

  • Ultra-Low Threshold and High Speed Electrically Driven Photonic Crystal Nanocavity Lasers and LEDs Conference on Lasers and Electro-Optics (CLEO) Vuckovic, J., Ellis, B., Shambat, G., Petykiewicz, J., Majumdar, A., Sarmiento, T., Mayer, M., Harris, J., Haller, E. IEEE. 2012
  • Photonic Crystal Nanocavity Lasers and Modulators 25th IEEE Photonics Conference (IPC) Vuckovic, J., Shambat, G., Petykiewicz, J., Ellis, B., Majumdar, A., Sarmiento, T., Mayer, M., Harris, J., Haller, E. IEEE. 2012: 459–460
  • Optical Fiber Tips Functionalized with Semiconductor Photonic Crystal Cavities Conference on Lasers and Electro-Optics (CLEO) Shambat, G., Provine, J., Rivoire, K., Sarmiento, T., Harris, J., Vuckovic, J. IEEE. 2012
  • Optical fiber tips functionalized with semiconductor photonic crystal cavities APPLIED PHYSICS LETTERS Shambat, G., Provine, J., Rivoire, K., Sarmiento, T., Harris, J., Vuckovic, J. 2011; 99 (19)

    View details for DOI 10.1063/1.3660278

    View details for Web of Science ID 000297030200002

  • Ultrafast direct modulation of a single-mode photonic crystal nanocavity light-emitting diode NATURE COMMUNICATIONS Shambat, G., Ellis, B., Majumdar, A., Petykiewicz, J., Mayer, M. A., Sarmiento, T., Harris, J., Haller, E. E., Vuckovic, J. 2011; 2

    Abstract

    Low-power and electrically controlled optical sources are vital for next generation optical interconnect systems to meet strict energy demands. Current optical transmitters consisting of high-threshold lasers plus external modulators consume far too much power to be competitive with future electrical interconnects. Here we demonstrate a directly modulated photonic crystal nanocavity light-emitting diode (LED) with 10 GHz modulation speed and less than 1 fJ per bit energy of operation, which is orders of magnitude lower than previous solutions. The device is electrically controlled and operates at room temperature, while the high modulation speed results from the fast relaxation of the quantum dots used as the active material. By virtue of possessing a small mode volume, our LED is intrinsically single mode and, therefore, useful for communicating information over a single narrowband channel. The demonstrated device is a major step forward in providing practical low-power and integrable sources for on-chip photonics.

    View details for DOI 10.1038/ncomms1543

    View details for Web of Science ID 000297686500026

    View details for PubMedID 22086339

  • Nanobeam photonic crystal cavity light-emitting diodes APPLIED PHYSICS LETTERS Shambat, G., Ellis, B., Petykiewicz, J., Mayer, M. A., Sarmiento, T., Harris, J., Haller, E. E., Vuckovic, J. 2011; 99 (7)

    View details for DOI 10.1063/1.3625432

    View details for Web of Science ID 000294208900005

  • Optical Gain in GaInNAs and GaInNAsSb Quantum Wells IEEE JOURNAL OF QUANTUM ELECTRONICS Ferguson, J. W., Blood, P., Smowton, P. M., Bae, H., Sarmiento, T., Harris, J. S., Tansu, N., Mawst, L. J. 2011; 47 (6): 870-877
  • Ultralow-threshold electrically pumped quantum-dot photonic-crystal nanocavity laser NATURE PHOTONICS Ellis, B., Mayer, M. A., Shambat, G., Sarmiento, T., Harris, J., Haller, E. E., Vuckovic, J. 2011; 5 (5): 297-300
  • Ultra-low Threshold Electrically Pumped Quantum Dot Photonic Crystal Nanocavity Laser Conference on Lasers and Electro-Optics (CLEO) Ellis, B., Mayer, M. A., Shambat, G., Sarmiento, T., Harris, J., Haller, E. E., Vuckovic, J. IEEE. 2011
  • Emerging applications for vertical cavity surface emitting lasers SEMICONDUCTOR SCIENCE AND TECHNOLOGY Harris, J. S., O'Sullivan, T., Sarmiento, T., Lee, M. M., Vo, S. 2011; 26 (1)
  • Electrically pumped photonic crystal nanocavity light sources using a laterally doped p-i-n junction APPLIED PHYSICS LETTERS Ellis, B., Sarmiento, T., Mayer, M., Zhang, B., Harris, J., Haller, E., Vuckovic, J. 2010; 96 (18)

    View details for DOI 10.1063/1.3425663

    View details for Web of Science ID 000277422000003

  • Nanobeam photonic crystal cavity quantum dot laser OPTICS EXPRESS Gong, Y., Ellis, B., Shambat, G., Sarmiento, T., Harris, J. S., Vuckovic, J. 2010; 18 (9): 8781-8789

    Abstract

    The lasing behavior of one dimensional GaAs nanobeam cavities with embedded InAs quantum dots is studied at room temperature. Lasing is observed throughout the quantum dot PL spectrum, and the wavelength dependence of the threshold is calculated. We study the cavity lasers under both 780 nm and 980 nm pump, finding thresholds as low as 0.3 microW and 19 microW for the two pump wavelengths, respectively. Finally, the nanobeam cavity laser wavelengths are tuned by up to 7 nm by employing a fiber taper in near proximity to the cavities. The fiber taper is used both to efficiently pump the cavity and collect the cavity emission.

    View details for Web of Science ID 000277082200006

    View details for PubMedID 20588722

  • Photoreflectance and photoluminescence study of GaInNAsSb layers lattice matched to InP JOURNAL OF APPLIED PHYSICS Kudrawiec, R., Sarmiento, T., Poloczek, P., Misiewicz, J., Harris, J. S. 2010; 107 (4)

    View details for DOI 10.1063/1.3280030

    View details for Web of Science ID 000275028900039

  • DESIGN AND GROWTH OF III-V NANOWIRE SOLAR CELL ARRAYS ON LOW COST SUBSTRATES 35th IEEE Photovoltaic Specialists Conference Gu, A., Huo, Y., Hu, S., Sarmiento, T., Pickett, E., Liang, D., Li, S., Lin, A., Thombare, S., Yu, Z., Fan, S., McIntyre, P., Cui, Y., Harris, J. IEEE. 2010: 2034–2037
  • FACETING AND DISORDER IN NANOWIRE SOLAR CELL ARRAYS 35th IEEE Photovoltaic Specialists Conference Pickett, E., Gu, A., Huo, Y., Garnett, E., Hu, S., Sarmiento, T., Thombare, S., Liang, D., Li, S., Cui, Y., McGehee, M., McIntyre, P., Harris, J. IEEE. 2010: 1848–1853
  • Electrically Pumped Photonic Crystal Nanocavities Using a Laterally Doped p-i-n Junction Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Ellis, B., Sarmiento, T., Mayer, M., Stone, P., Beeman, J., Zhang, B., Dubon, O., Haller, E., Yamamoto, Y., Harris, J., Vuckovic, J. IEEE. 2010
  • Nonradiative recombination in 1.56 mu m GaInNAsSb/GaNAs quantum-well lasers APPLIED PHYSICS LETTERS Ferguson, J. W., Smowton, P. M., Blood, P., Bae, H., Sarmiento, T., Harris, J. S. 2009; 95 (23)

    View details for DOI 10.1063/1.3271182

    View details for Web of Science ID 000272627700004

  • GaAs-based 1.53 mu m GaInNAsSb vertical cavity surface emitting lasers ELECTRONICS LETTERS Sarmiento, T., Bae, H. P., O'Sullivan, T. D., Harris, J. S. 2009; 45 (19): 978-U28
  • Electrically controlled modulation in a photonic crystal nanocavity OPTICS EXPRESS Englund, D., Ellis, B., Edwards, E., Sarmiento, T., Harris, J. S., Miller, D. A., Vuckovic, J. 2009; 17 (18): 15409-15419

    Abstract

    We describe a compact modulator based on a photonic crystal nanocavity whose resonance is electrically controlled through an integrated p-i-n junction. The sub-micron size of the nanocavity promises very low capacitance, high bandwidth, and efficient on-chip integration in optical interconnects.

    View details for Web of Science ID 000269781700003

    View details for PubMedID 19724539

  • Contactless electroreflectance of GaInNAsSb/GaNAs/GaAs quantum wells emitting at 1.5-1.65 mu m: Broadening of the fundamental transition APPLIED PHYSICS LETTERS Kudrawiec, R., Poloczek, P., Misiewicz, J., Bae, H. P., Sarmiento, T., Bank, S. R., Yuen, H. B., Wistey, M. A., Harris, J. S. 2009; 94 (3)

    View details for DOI 10.1063/1.3073718

    View details for Web of Science ID 000262724000010

  • High Efficiency Solar Cells based on Spontaneous Emission Inhibition in Photonic Crystals Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Ellis, B., Sarmiento, T., Harris, J., Vuckovic, J. IEEE. 2009: 2659–2660
  • 1528 nm GaInNAsSb/GaAs Vertical Cavity Surface Emitting Lasers Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Sarmiento, T., Bae, H., O'Sullivan, T. D., Harris, J. S. IEEE. 2009: 1629–1630
  • GaInNAsSb/GaAs vertical cavity surface-emitting lasers (VCSELs): current challenges and techniques to realize multiple-wavelength laser arrays at 1.55 mu m Conference on Vertical-Cavity Surface-Emitting Lasers XII Gobe, M., Bae, H. P., Sarmiento, T., Harris, J. S. SPIE-INT SOC OPTICAL ENGINEERING. 2008

    View details for DOI 10.1117/12.762311

    View details for Web of Science ID 000254737900019

  • Experimental investigation of temperature dependence of 1.55 mu m GaInNAsSb/GaNAs QW lasers grown in MBE IEEE 21st International Semiconductor Laser Conference Bae, H., Sarmiento, T., Harris, J. S. IEEE. 2008: 59–60
  • Development of GaInNAsSb alloys: Growth, band structure, optical properties and applications PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Harris, J. S., Kudrawiec, R., Yuen, H. B., Bank, S. R., Bae, H. P., Wistey, M. A., Jackrel, D., Pickett, E. R., Sarmiento, T., Goddard, L. L., Lordi, V., Gugov, T. 2007; 244 (8): 2707-2729
  • Temperature dependencies of annealing behaviors of GaInNAsSb/GaNAs quantum wells for long wavelength dilute-nitride lasers APPLIED PHYSICS LETTERS Bae, H. P., Bank, S. R., Yuen, H. B., Sarmiento, T., Pickett, E. R., Wistey, M. A., Harris, J. S. 2007; 90 (23)

    View details for DOI 10.1063/1.2746944

    View details for Web of Science ID 000247145500019

  • Thermally induced relaxation in GaInNAsSb quantum well structures Symposium on Semiconductor Defect Engineering Materials, Synthetic Structures and Devices II held at the 2007 MRS Spring Meeting Pickett, E., Bank, S., Yuen, H., Bae, H., Sarmiento, T., Marshall, A., Harris, J. MATERIALS RESEARCH SOCIETY. 2007: 105–110
  • Low-threshold CW 1.55-mu m GaAs-based lasers Conference on Optical Fiber Communications/National Fiber Optic Engineers Conference Bank, S. R., Bae, H. P., Yuen, H. B., Goddard, L. L., Wistey, M. A., Sarmiento, T., Harris, J. S. OPTICAL SOC AMERICA. 2006: 1646–1648