The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Mankei Tsang - One of the best experts on this subject based on the ideXlab platform.

  • Semiparametric estimation for incoherent optical imaging.
    Physical Review Research, 2019
    Co-Authors: Mankei Tsang
    Abstract:

    The theory of semiparametric estimation offers an elegant way of computing the Cram\'er-Rao bound for a parameter of interest in the midst of infinitely many nuisance parameters. Here I apply the theory to the problem of moment estimation for incoherent imaging under the effects of diffraction and Photon Shot Noise. Using a Hilbert-space formalism designed for Poisson processes, I derive exact semiparametric Cram\'er-Rao bounds and efficient estimators for both direct imaging and a quantum-inspired measurement method called spatial-mode demultiplexing (SPADE). The results establish the superiority of SPADE even when little prior information about the object is available.

  • subdiffraction incoherent optical imaging via spatial mode demultiplexing semiclassical treatment
    Physical Review A, 2018
    Co-Authors: Mankei Tsang
    Abstract:

    I present a semiclassical analysis of a spatial-mode demultiplexing (SPADE) measurement scheme for far-field incoherent optical imaging under the effects of diffraction and Photon Shot Noise. Building on previous results that assume two point sources or the Gaussian point-spread function, I generalize SPADE for a larger class of point-spread functions and evaluate its errors in estimating the moments of an arbitrary subdiffraction object. Compared with the limits to direct imaging set by the Cram\'er-Rao bounds, the results show that SPADE can offer far superior accuracy in estimating the second and higher-order moments.

  • subdiffraction incoherent optical imaging via spatial mode demultiplexing
    New Journal of Physics, 2017
    Co-Authors: Mankei Tsang
    Abstract:

    I propose a spatial-mode demultiplexing (SPADE) measurement scheme for the far-field imaging of spatially incoherent optical sources. For any object too small to be resolved by direct imaging under the diffraction limit, I show that SPADE can estimate its second or higher moments much more precisely than direct imaging can fundamentally do in the presence of Photon Shot Noise. I also prove that SPADE can approach the optimal precision allowed by quantum mechanics in estimating the location and scale parameters of a subdiffraction object. Realizable with far-field linear optics and Photon counting, SPADE is expected to find applications in both fluorescence microscopy and astronomy.

Dmitry Budker - One of the best experts on this subject based on the ideXlab platform.

  • Miniature Cavity-Enhanced Diamond Magnetometer
    Phys.Rev.Applied, 2017
    Co-Authors: Georgios Chatzidrosos, Nathan Leefer, Kasper Jensen, Yannick Dumeige, Arne Wickenbrock, Lykourgos Bougas, Dmitry Budker
    Abstract:

    We present a highly sensitive miniaturized cavity-enhanced room-temperature magnetic-field sensor based on nitrogen-vacancy centers in diamond. The magnetic resonance signal is detected by probing absorption on the 1042-nm spin-singlet transition. To improve the absorptive signal the diamond is placed in an optical resonator. The device has a magnetic-field sensitivity of 28 pT/Hz, a projected Photon Shot-Noise-limited sensitivity of 22 pT/Hz, and an estimated quantum projection-Noise-limited sensitivity of 0.43 pT/Hz with the sensing volume of ∼390 μm×4500 μm2. The presented miniaturized device is the basis for an endoscopic magnetic-field sensor for biomedical applications.

  • Cavity-enhanced room-temperature magnetometry using absorption by nitrogen-vacancy centers in diamond
    Physical Review Letters, 2014
    Co-Authors: Kasper Jensen, B. Patton, Pauli Kehayias, Andrey Jarmola, Nathan Leefer, Víctor M. Acosta, Yannick Dumeige, Dmitry Budker
    Abstract:

    We demonstrate a cavity-enhanced room-temperature magnetic field sensor based on nitrogen-vacancy centers in diamond. Magnetic resonance is detected using absorption of light resonant with the 1042 nm spin-singlet transition. The diamond is placed in an external optical cavity to enhance the absorption, and significant absorption is observed even at room temperature. We demonstrate a magnetic field sensitivity of 2.5 nT/sqrt(Hz), and project a Photon Shot-Noise-limited sensitivity of 70 pT/sqrt(Hz) for a few mW of infrared light, and a quantum projection-Noise-limited sensitivity of 250 fT/sqrt(Hz) for the sensing volume of 90 um x 90 um 200 um.

  • room temperature operation of a radiofrequency diamond magnetometer near the Shot Noise limit
    arXiv: Instrumentation and Detectors, 2012
    Co-Authors: Chang S Shin, Víctor M. Acosta, Dmitry Budker, Claudia E Avalos, Mark C Butler, David Trease, Scott J Seltzer, Peter J Mustonen, Daniel J Kennedy, Alexander Pines
    Abstract:

    We operate a nitrogen vacancy (NV-) diamond magnetometer at ambient temperatures and study the dependence of its bandwidth on experimental parameters including optical and microwave excitation powers. We introduce an analytical theory that yields an explicit formula for the response of an ensemble of NV- spins to an oscillating magnetic field, such as in NMR applications. We measure a detection bandwidth of 1.6 MHz and a sensitivity of 4.6 nT/Hz^(1/2), unprecedented in a detector with this active volume and close to the Photon Shot Noise limit of our experiment.

  • broadband magnetometry by infrared absorption detection of nitrogen vacancy ensembles in diamond
    Applied Physics Letters, 2010
    Co-Authors: Víctor M. Acosta, L. J. Zipp, Andrey Jarmola, Erik Bauch, M P Ledbetter, Dmitry Budker
    Abstract:

    We demonstrate magnetometry by detection of the spin state of high-density nitrogen-vacancy ensembles in diamond using optical absorption at 1042 nm. With this technique, measurement contrast, and collection efficiency can approach unity, leading to an increase in magnetic sensitivity compared to the more common method of collecting red fluorescence. Working at 75 K with a sensor with effective volume 50×50×300 μm3, we project Photon Shot-Noise limited sensitivity of 5 pT in one second of acquisition and bandwidth from dc to a few megahertz. Operation in a gradiometer configuration yields a Noise floor of 7 nTrms at ∼110 Hz in one second of acquisition.

  • Broadband magnetometry by infrared-absorption detection of nitrogen-vacancy ensembles in diamond
    Applied Physics Letters, 2010
    Co-Authors: Víctor M. Acosta, L. J. Zipp, Andrey Jarmola, Erik Bauch, M P Ledbetter, Dmitry Budker
    Abstract:

    We demonstrate magnetometry by detection of the spin state of high-density nitrogen-vacancy ensembles in diamond using optical absorption at 1042 nm. With this technique, measurement contrast, and collection efficiency can approach unity, leading to an increase in magnetic sensitivity compared to the more common method of collecting red fluorescence. Working at 75 K with a sensor with effective volume $50 \times 50 \times 300$ microns^3, we project Photon Shot-Noise limited sensitivity of 5 pT in one second of acquisition and bandwidth from dc to a few megahertz. Operation in a gradiometer configuration yields a Noise floor of 7 nTrms at ~110 Hz in one second of acquisition.

Víctor M. Acosta - One of the best experts on this subject based on the ideXlab platform.

  • Cavity-enhanced room-temperature magnetometry using absorption by nitrogen-vacancy centers in diamond
    Physical Review Letters, 2014
    Co-Authors: Kasper Jensen, B. Patton, Pauli Kehayias, Andrey Jarmola, Nathan Leefer, Víctor M. Acosta, Yannick Dumeige, Dmitry Budker
    Abstract:

    We demonstrate a cavity-enhanced room-temperature magnetic field sensor based on nitrogen-vacancy centers in diamond. Magnetic resonance is detected using absorption of light resonant with the 1042 nm spin-singlet transition. The diamond is placed in an external optical cavity to enhance the absorption, and significant absorption is observed even at room temperature. We demonstrate a magnetic field sensitivity of 2.5 nT/sqrt(Hz), and project a Photon Shot-Noise-limited sensitivity of 70 pT/sqrt(Hz) for a few mW of infrared light, and a quantum projection-Noise-limited sensitivity of 250 fT/sqrt(Hz) for the sensing volume of 90 um x 90 um 200 um.

  • room temperature operation of a radiofrequency diamond magnetometer near the Shot Noise limit
    arXiv: Instrumentation and Detectors, 2012
    Co-Authors: Chang S Shin, Víctor M. Acosta, Dmitry Budker, Claudia E Avalos, Mark C Butler, David Trease, Scott J Seltzer, Peter J Mustonen, Daniel J Kennedy, Alexander Pines
    Abstract:

    We operate a nitrogen vacancy (NV-) diamond magnetometer at ambient temperatures and study the dependence of its bandwidth on experimental parameters including optical and microwave excitation powers. We introduce an analytical theory that yields an explicit formula for the response of an ensemble of NV- spins to an oscillating magnetic field, such as in NMR applications. We measure a detection bandwidth of 1.6 MHz and a sensitivity of 4.6 nT/Hz^(1/2), unprecedented in a detector with this active volume and close to the Photon Shot Noise limit of our experiment.

  • broadband magnetometry by infrared absorption detection of nitrogen vacancy ensembles in diamond
    Applied Physics Letters, 2010
    Co-Authors: Víctor M. Acosta, L. J. Zipp, Andrey Jarmola, Erik Bauch, M P Ledbetter, Dmitry Budker
    Abstract:

    We demonstrate magnetometry by detection of the spin state of high-density nitrogen-vacancy ensembles in diamond using optical absorption at 1042 nm. With this technique, measurement contrast, and collection efficiency can approach unity, leading to an increase in magnetic sensitivity compared to the more common method of collecting red fluorescence. Working at 75 K with a sensor with effective volume 50×50×300 μm3, we project Photon Shot-Noise limited sensitivity of 5 pT in one second of acquisition and bandwidth from dc to a few megahertz. Operation in a gradiometer configuration yields a Noise floor of 7 nTrms at ∼110 Hz in one second of acquisition.

  • Broadband magnetometry by infrared-absorption detection of nitrogen-vacancy ensembles in diamond
    Applied Physics Letters, 2010
    Co-Authors: Víctor M. Acosta, L. J. Zipp, Andrey Jarmola, Erik Bauch, M P Ledbetter, Dmitry Budker
    Abstract:

    We demonstrate magnetometry by detection of the spin state of high-density nitrogen-vacancy ensembles in diamond using optical absorption at 1042 nm. With this technique, measurement contrast, and collection efficiency can approach unity, leading to an increase in magnetic sensitivity compared to the more common method of collecting red fluorescence. Working at 75 K with a sensor with effective volume $50 \times 50 \times 300$ microns^3, we project Photon Shot-Noise limited sensitivity of 5 pT in one second of acquisition and bandwidth from dc to a few megahertz. Operation in a gradiometer configuration yields a Noise floor of 7 nTrms at ~110 Hz in one second of acquisition.

Adam Sears - One of the best experts on this subject based on the ideXlab platform.

  • the flux qubit revisited to enhance coherence and reproducibility
    Nature Communications, 2016
    Co-Authors: Simo Gustavsso, Archana Kamal, Jeffrey Irenbaum, Adam Sears, David Hove, Theodore Gudmundse, Danna Rosenberg, Gabriel Samach, S J Webe, Jonily Yode
    Abstract:

    The scalable application of quantum information science will stand on reproducible and controllable high-coherence quantum bits (qubits). Here, we revisit the design and fabrication of the superconducting flux qubit, achieving a planar device with broad-frequency tunability, strong anharmonicity, high reproducibility and relaxation times in excess of 40 μs at its flux-insensitive point. Qubit relaxation times T1 across 22 qubits are consistently matched with a single model involving resonator loss, ohmic charge Noise and 1/f-flux Noise, a Noise source previously considered primarily in the context of dephasing. We furthermore demonstrate that qubit dephasing at the flux-insensitive point is dominated by residual thermal-Photons in the readout resonator. The resulting Photon Shot Noise is mitigated using a dynamical decoupling protocol, resulting in T2≈85 μs, approximately the 2T1 limit. In addition to realizing an improved flux qubit, our results uniquely identify Photon Shot Noise as limiting T2 in contemporary qubits based on transverse qubit–resonator interaction. Scalable quantum information processing requires controllable high-coherence qubits. Here, the authors present superconducting flux qubits with broad frequency tunability, strong anharmonicity and high reproducibility, identifying Photon Shot Noise as the main source of dephasing for further improvements.

  • Photon Shot Noise dephasing in the strong dispersive limit of circuit qed
    Physical Review B, 2012
    Co-Authors: Adam Sears, Andrei Petrenko, Gianluigi Catelani, L Sun, Hanhee Paik, Gerhard Kirchmair, Luigi Frunzio, L I Glazman, S M Girvin, R J Schoelkopf
    Abstract:

    We study the Photon Shot Noise dephasing of a superconducting transmon qubit in the strong-dispersive limit, due to the coupling of the qubit to its readout cavity. As each random arrival or departure of a Photon is expected to completely dephase the qubit, we can control the rate at which the qubit experiences dephasing events by varying in situ the cavity mode population and decay rate. This allows us to verify a pure dephasing mechanism that matches theoretical predictions, and in fact explains the increased dephasing seen in recent transmon experiments as a function of cryostat temperature. We observe large increases in coherence times as the cavity is decoupled from the environment, and after implementing filtering find that the intrinsic coherence of small Josephson junctions when corrected with a single Hahn echo is greater than several hundred microseconds. Similar filtering and thermalization may be important for other qubit designs in order to prevent Photon Shot Noise from becoming the dominant source of dephasing.

Jinho Ahn - One of the best experts on this subject based on the ideXlab platform.

  • Attenuated phase-shift mask for mitigation of Photon Shot Noise effect in contact hole pattern for extreme ultraviolet lithography
    Applied Physics Express, 2014
    Co-Authors: Jung Sik Kim, Seongchul Hong, Jae Uk Lee, Seung Min Lee, Jinho Ahn
    Abstract:

    In extreme ultraviolet lithography (EUVL), insufficient light source power is the biggest concern for high-volume manufacturing. Additionally, the Photon Shot Noise (PSN) effect is believed to be the main source of degradation in various aspects of imaging performance. In this study, we propose an attenuated phase-shift mask (PSM) as a solution to both of these issues, yielding improved mask performance for the printing of small contact hole (C/H) patterns. Our PSM shows superior imaging performance over that of a binary intensity mask. We speculate that the stochastic imaging characteristics are improved by the enhanced diffraction efficiency of the PSM.

  • Stochastic Patterning Simulation Using Attenuated Phase-Shift Mask for Extreme Ultraviolet Lithography
    Applied Physics Express, 2013
    Co-Authors: Seongchul Hong, Jae Uk Lee, Seung Min Lee, Seejun Jeong, Jinho Ahn
    Abstract:

    In extreme ultraviolet lithography, the Photon Shot Noise effect is a main cause of low-quality imaging characteristics such as line edge roughness and critical dimension (CD) nonuniformity. In this study, the stochastic imaging property of an attenuated phase-shift mask (PSM) was evaluated, and the results showed that "informative" Photons from the first order diffraction are essential for mitigating the Photon Shot Noise effect. This structure exhibits a reflectivity of ~6% at the absorber stack and a phase shift of 180° at 13.5 nm wavelength. The improved stochastic patterning properties of the PSM were compared with those of a conventional binary intensity mask.