实际环境对量子激光雷达性能的影响

Effects of real environments on the performance of quantum Lidar

研究了损耗和相位噪声对奇相干态（OCRS）量子激光雷达性能的影响。利用条件概率的一般表达式和奇偶光子计数探测方法推导了马赫－增德尔干涉4％（MZI）输出信号的平均值和相位灵敏度。从信号平均值的表达式中可以看出光子数损耗破坏了信号的相干性进而导致了激光雷达性能的下降。数值计算结果表明：输出信号的干涉花样中出现了奇偶相干项，且奇相干项对损耗及其敏感；系统的输出性能只有在小损耗区域内优于传统的激光雷达。而在噪声环境中，在噪声区域K〉0．3内，奇相干态的信号的分辨率优于相干态，而在K〉0．06区域内，奇相干态的奇偶光子计数探测信号的灵敏度好于相干态。

The effects of loss and noise （real environments） on the performance of quantum lidar with odd coherent superposition states source （OCRS） was investigeted. The general expression of conditional probabilities and parity photon counting measurement strategies were exploited to derive the mean value of the output signal and its phase sensitivity from the Mach-Zehnder interferometer （MZI）. It can be found from the output signal that loss destroys the coherence and further descents the performance of lidar. The numerical calculation shows that the odd and even interference fringes emerge in the whole interference pattern, and the odd interference term which represents the coherence is extremely sensitive to particle loss. The odd coherent states quantum lidar outperforms the performance achieved by the traditional coherent states （CS） lidar only in small loss regimes. However, in the noisy environments, OCRS gives the better resolution and sensitivity than CS in the regions of K〉0.3 and K〉0.06, respectively.