Quantum illumination for enhanced detection of Rayleigh-fading targets
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PhysRevA.96.020302.pdf
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303.28 KB
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Author(s)
Zhuang, Quntao
Zhang, Zheshen
Shapiro, Jeffrey H
Date Issued
August 2017
Journal
Physical Review A
Publisher
American Physical Society
Citation
Zhuang, Quntao, et al. “Quantum Illumination for Enhanced Detection of Rayleigh-Fading Targets.” Physical Review A, vol. 96, no. 2, Aug. 2017. © 2017 American Physical Society
Version
Final published version
Abstract
Quantum illumination (QI) is an entanglement-enhanced sensing system whose performance advantage over a comparable classical system survives its usage in an entanglement-breaking scenario plagued by loss and noise. In particular, QI's error-probability exponent for discriminating between equally likely hypotheses of target absence or presence is 6 dB higher than that of the optimum classical system using the same transmitted power. This performance advantage, however, presumes that the target return, when present, has known amplitude and phase, a situation that seldom occurs in light detection and ranging (lidar) applications. At lidar wavelengths, most target surfaces are sufficiently rough that their returns are speckled, i.e., they have Rayleigh-distributed amplitudes and uniformly distributed phases. QI's optical parametric amplifier receiver—which affords a 3 dB better-than-classical error-probability exponent for a return with known amplitude and phase—fails to offer any performance gain for Rayleigh-fading targets. We show that the sum-frequency generation receiver [Zhuang et al., Phys. Rev. Lett. 118, 040801 (2017)]—whose error-probability exponent for a nonfading target achieves QI's full 6 dB advantage over optimum classical operation—outperforms the classical system for Rayleigh-fading targets. In this case, QI's advantage is subexponential: its error probability is lower than the classical system's by a factor of 1/ln(M[ bar over κ]N[subscript S]/N[subscript B]), when M[bar over κ]N[subscript S]/N[subscript B]≫1, with M≫1 being the QI transmitter's time-bandwidth product, N[subscript S]≪1 its brightness, [bar over κ] the target return's average intensity, and N[subscript B] the background light's brightness.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1103/PhysRevA.96.020302
