We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon dete... more We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array, as well as characterization measurements are discussed.
ABSTRACT We measure a saturation of the internal quantum efficiency of superconducting nanowire s... more ABSTRACT We measure a saturation of the internal quantum efficiency of superconducting nanowire single-photon detectors based on a Mo0.75Ge0.25 alloy with peak system detection efficiency of 30%.
ABSTRACT Since the first reported detection of a single photon using a superconducting nanowire i... more ABSTRACT Since the first reported detection of a single photon using a superconducting nanowire in 2001, rapid progress has been made in the development and application of superconducting nanowire single photon detectors (SNSPD or SSPD). I will briefly describe use of these detectors in new applications, progress in detector developments, and describe areas of research and their potential impact.
Rochester Conference on Coherence and Quantum Optics (CQO-11), 2019
We present a fiber-coupled single-photon detector with 98% system detection efficiencies at 1550 ... more We present a fiber-coupled single-photon detector with 98% system detection efficiencies at 1550 nm. We characterize beam divergence within the optical stack and the electronic compensations required for large-active-area detectors.
We developed superconducting nanowire single-photon detectors based on tungsten silicide, which s... more We developed superconducting nanowire single-photon detectors based on tungsten silicide, which show saturated internal detection efficiency up to a wavelength of 10 μm. These detectors are promising for applications in the mid-infrared requiring sub-nanosecond timing, ultra-high gain stability, low dark counts, and high efficiency, such as chemical sensing, LIDAR, dark matter searches, and exoplanet spectroscopy.
We present a loophole-free violation of local realism using entangled photon pairs. We ensure tha... more We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment.
Bulletin of the American Physical Society, Mar 19, 2013
We report progress toward the experimental realization of information-efficient quantum imaging, ... more We report progress toward the experimental realization of information-efficient quantum imaging, here at two bits per photon. A heralded single-photon source ($ g^{2}(0)< 0.08$) is used as the input to a 4x4 multiport interferometer, compactly implemented using both polarization and spatial degrees of freedom. The interferometer can be used to read out all 4 Hadamard phase codes with a single photon. We investigate the use of cavity-enhanced spontaneous parametric downconversion for the coherent source of heralded photons. ...
Till J. Weinhold1, Devin H. Smith1, Geoff Gillett1, Marcelo P. de Almeida1, Cyril Branciard2, Ale... more Till J. Weinhold1, Devin H. Smith1, Geoff Gillett1, Marcelo P. de Almeida1, Cyril Branciard2, Alessandro Fedrizzi1, Adriana Lita3, Brice Calkins3, Thomas Gerrits3, Sae Woo Nam3, Andrew G. White1 1Centre for Engineered Quantum Systems and Centre for Quantum Computation and Communication Technology (Australian Research Council), School of Mathematics and Physics, University of Queensland, 4072 Brisbane, QLD, Australia 2School of Mathematics and Physics, University of Queensland, 4072 Brisbane, QLD, Australia 3National Institute of Standards and ...
Local realism is the worldview in which physical properties of objects exist independently of mea... more Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell's inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. Here, we report a Bell test that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance. The purely statistical probability of our results to occur under local realism does not exceed 3.74×10^{-31}, corresponding to an 11.5 standard deviation effect.
There is significant interest in the structure of metal thin films due to their wide application ... more There is significant interest in the structure of metal thin films due to their wide application as critical components in electronic, magnetic and optical devices. The functionality of these devices is determined by the films physical structure that includes surface morphology and in the case of polycrystalline films, grains size distribution and crystallographic orientation. Many processing schemes have been developed to control film microstructure and surface roughness in practice, however, they usually have limited application related to specific material systems or growth conditions. A comprehensive model for structure development that incorporate deposition conditions and substrate material properties is still lacking. This thesis goal is to further the present understanding on polycrystalline film structure development with an emphasis on the correlation between surface morphology and underlying microstructure evolution. The growth of polycrystalline thin films at different d...
We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon dete... more We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array, as well as characterization measurements are discussed.
ABSTRACT We measure a saturation of the internal quantum efficiency of superconducting nanowire s... more ABSTRACT We measure a saturation of the internal quantum efficiency of superconducting nanowire single-photon detectors based on a Mo0.75Ge0.25 alloy with peak system detection efficiency of 30%.
ABSTRACT Since the first reported detection of a single photon using a superconducting nanowire i... more ABSTRACT Since the first reported detection of a single photon using a superconducting nanowire in 2001, rapid progress has been made in the development and application of superconducting nanowire single photon detectors (SNSPD or SSPD). I will briefly describe use of these detectors in new applications, progress in detector developments, and describe areas of research and their potential impact.
Rochester Conference on Coherence and Quantum Optics (CQO-11), 2019
We present a fiber-coupled single-photon detector with 98% system detection efficiencies at 1550 ... more We present a fiber-coupled single-photon detector with 98% system detection efficiencies at 1550 nm. We characterize beam divergence within the optical stack and the electronic compensations required for large-active-area detectors.
We developed superconducting nanowire single-photon detectors based on tungsten silicide, which s... more We developed superconducting nanowire single-photon detectors based on tungsten silicide, which show saturated internal detection efficiency up to a wavelength of 10 μm. These detectors are promising for applications in the mid-infrared requiring sub-nanosecond timing, ultra-high gain stability, low dark counts, and high efficiency, such as chemical sensing, LIDAR, dark matter searches, and exoplanet spectroscopy.
We present a loophole-free violation of local realism using entangled photon pairs. We ensure tha... more We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment.
Bulletin of the American Physical Society, Mar 19, 2013
We report progress toward the experimental realization of information-efficient quantum imaging, ... more We report progress toward the experimental realization of information-efficient quantum imaging, here at two bits per photon. A heralded single-photon source ($ g^{2}(0)< 0.08$) is used as the input to a 4x4 multiport interferometer, compactly implemented using both polarization and spatial degrees of freedom. The interferometer can be used to read out all 4 Hadamard phase codes with a single photon. We investigate the use of cavity-enhanced spontaneous parametric downconversion for the coherent source of heralded photons. ...
Till J. Weinhold1, Devin H. Smith1, Geoff Gillett1, Marcelo P. de Almeida1, Cyril Branciard2, Ale... more Till J. Weinhold1, Devin H. Smith1, Geoff Gillett1, Marcelo P. de Almeida1, Cyril Branciard2, Alessandro Fedrizzi1, Adriana Lita3, Brice Calkins3, Thomas Gerrits3, Sae Woo Nam3, Andrew G. White1 1Centre for Engineered Quantum Systems and Centre for Quantum Computation and Communication Technology (Australian Research Council), School of Mathematics and Physics, University of Queensland, 4072 Brisbane, QLD, Australia 2School of Mathematics and Physics, University of Queensland, 4072 Brisbane, QLD, Australia 3National Institute of Standards and ...
Local realism is the worldview in which physical properties of objects exist independently of mea... more Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell's theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell's inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. Here, we report a Bell test that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance. The purely statistical probability of our results to occur under local realism does not exceed 3.74×10^{-31}, corresponding to an 11.5 standard deviation effect.
There is significant interest in the structure of metal thin films due to their wide application ... more There is significant interest in the structure of metal thin films due to their wide application as critical components in electronic, magnetic and optical devices. The functionality of these devices is determined by the films physical structure that includes surface morphology and in the case of polycrystalline films, grains size distribution and crystallographic orientation. Many processing schemes have been developed to control film microstructure and surface roughness in practice, however, they usually have limited application related to specific material systems or growth conditions. A comprehensive model for structure development that incorporate deposition conditions and substrate material properties is still lacking. This thesis goal is to further the present understanding on polycrystalline film structure development with an emphasis on the correlation between surface morphology and underlying microstructure evolution. The growth of polycrystalline thin films at different d...
Uploads
Papers by Adriana Lita