Super-Resolving Quantum Radar: Coherent-State Sources with Homodyne Detection Suffice to Beat the Diffraction Limit

Abstract

There has been much recent interest in quantum metrology for applications to sub-Raleigh ranging and remote sensing such as in quantum radar. For quantum radar, atmospheric absorption and diffraction rapidly degrades any actively transmitted quantum states of light, such as N00N states, so that for this high-loss regime the optimal strategy is to transmit coherent states of light, which suffer no worse loss than the linear Beer's law for classical radar attenuation, and which provide sensitivity at the shot-noise limit in the returned power. We show that coherent radar radiation sources, coupled with a quantum homodyne detection scheme, provide both longitudinal and angular super-resolution much below the Rayleigh diffraction limit, with sensitivity at shot-noise in terms of the detected photon power. Our approach provides a template for the development of a complete super-resolving quantum radar system with currently available technology.

Design of an on-Chip Room Temperature Group-IV Quantum Photonic Chem/Bio Interferometric Sensor Based on Parity Detection

“…The probability oscillates times faster than the measured intensity in the classic case, , so showing clearly the super-resolution effect. Moreover, the probability does not impose any limitation on the value of for all applications where the super-resolution is the performance parameter of interest, such as optical lithography [ 15 ], matter-wave interferometry [ 16 ], and radar ranging [ 17 ]. In this context, even higher N00N states ( = 5) have been realized by mixing quantum and classical light and using the discrete optics approach, where visibility values around 95%, 86%, 74%, 42% for = 2,3,4,5, respectively, have been obtained [ 18 ].…”

Cross Section Equivalence Between Photons and Non-Relativistic Massive Particles for Targets With Complex Geometries

“…Thus, using purely particle considerations, we have arrived at the exact same equation for the QRCS using single photon illumination [2]. We can go a step further and relax the monostatic geometry assumption in Equation (5), as well as not imposing the extra factor of 1 introduced by a complex exponential in terms of the target distance used in Equation (7). This provides coordinates that are only dependent on target geometry, not object distance.…”

“…Objects viewed with a quantum radar exhibit increased QRCS sidelobe returns, resolution, and signal-to-noise ratio (SNR) in comparison to classical radar with the same transmit power under certain regimes [1,2]. There are many mechanisms by which a quantum radar achieves an advantage over classical radar [6][7][8], and it is these results that prompt further study into this promising field.…”

Quantum Optical Technologies for Metrology, Sensing, and Imaging

“…Likewise, metrology, which is also a science based on information acquisition, processing, and estimation, has been revisited to include the effects of quantum mechanics too. Quantum metrology [6] has been found to enable measurements with precisions that surpass the classical limit, and has grown into an exciting new area of research with potential applications, e.g., in gravitational wave detection [7], quantum positioning and clock synchronization [8], quantum frequency standards [9], quantum sensing [10], [11], quantum radar and LIDAR [12], [13], quantum imaging [14], [15] and quantum lithography [16]- [18]. Fig.…”