关键词: 量子干涉雷达/
大气损耗/
超分辨率
English Abstract
Influence of atmosphere attenuation on quantum interferometric radar
Wang Shu1,2,Ren Yi-Chong1,
Rao Rui-Zhong1,
Miao Xi-Kui3
1.Key Laboratory of Atmospheric Composition and Optical Radiation, Anhui Institute of Optics and Fine Mechanics, Chinese Academy Sciences, Hefei 230031, China;
2.University of Science and Technology of China, Hefei 230026, China;
3.Key Laboratory of Electro-Optical Countermeasures Test and Evaluation Technology, Luoyang 471003, China
Fund Project:Project supported by the National Science Foundation of China (Grant No.11574295) and the Key Laboratory of ElectroOptical Countermeasures Test and Evaluation Technology,China (Grant No.GKCP2016001).Received Date:10 January 2017
Accepted Date:03 May 2017
Published Online:05 August 2017
Abstract:There has been aroused much interest in quantum metrology such as quantum radar, due to its applications in sub-Raleigh ranging and remote sensing. For quantum radar, the atmospheric absorption and diffraction rapidly degrade any actively transmitted quantum states of light, such as N00N and MM' states. Thus for the high-loss condition, the optimal strategy is to transmit coherent state of light, which can only provide sensitivity at the shot-noise limit but suffer no worse loss than the linear Beer's law for classical radar attenuation.In this paper, the target detection theory of quantum interferometric radar in the presence of photon loss is thoroughly investigated with the model of Mach-Zehnder interferometer, and the dynamic evolution of the quantum light field in the detecting process is also investigated. We utilize the parity operator to detect the return signal of quantum interferometric radar with coherent-state source. Then we compare the detection result of quantum radar with that of classical radar, which proves that the quantum radar scheme that employs coherent radiation sources and parity operator detection can provide an N-fold super-resolution, which is much below the Rayleigh diffraction limit; besides, the sensitivity of this scheme can also achieve the shot-noise-limit.Also, we analyze the effect of atmospheric attenuation on the performance of quantum radar, and find that the sensitivity is seriously influenced by atmospheric attenuation:only when the reference beam and the detection beam have the same transmissivity, will the sensitivity increase monotonically with increasing the photon number per pulse N, otherwise it first increases and then decreases with increasing N. Further, the sensivity is directly proportional to 1/N for the first case.In conclusion, we investigate the effects of atmospheric absorption on the resolution and sensitivity of quantum radar, and find that one can overcome the harmful effects of atmospheric attenuation by adjusting the transmissivity of reference beam to the atmospheric transmittance.
Keywords: quantum interferometric radar/
atmospheric absorption/
super-resolution
