Super-sensitive detection of quantum interferometer in atmospheric environment

Abstract

With squeezed states or entangled states being the source, quantum metrology, imaging and sensing can break the standard quantum limit (SQL), even reach the Heisenberg limit (HL), which is difficult to achieve by traditional methods. However, the photon loss or phase fluctuation caused by the atmospheric attenuation and turbulence cannot be ignored in the actual application. Atmospheric transmittance and phase fluctuation are related to the detection distance, and the phase sensitivity becomes worse as the distance increases. As the functions of distance, the photon loss and phase fluctuation are uniformly expressed according to the introduction of atmospheric attenuation coefficient, turbulence structure constant and receive aperture size in this paper. The density matrixes and phase sensitivities of N00N states and M&M′ states in the atmospheric environment are proposed in terms of distance variables. Then the quantitative computation of super-sensitive distance is carried out. SQL-contour is proposed to describe the super-sensitive ability of the quantum interferometer for the affection from both photon loss and phase fluctuation. The simulation results show that, in atmospheric environment the super-sensitive distance can reach hundreds of meters. M&M′ states with less total photon number are more likely to reflect the advantage of super-sensitivity. SQL-contour can provide references for interferometric source choosing.

创新点

以马赫曾德干涉仪(MZI)为基础, 以探测距离为基本变量, 给出了在光子损耗及相位波动共同影响下的N00N态与M&M’态的密度矩阵及相位探测精度, 并计算了不同条件下的超灵敏作用距离。同时提出以SQL等高线表征上述两种因素共同影响下量子干涉仪超灵敏探测性能的方法。仿真结果表明, 在典型大气环境下, 光量子干涉的超灵敏作用距离能够达到百米量级且总光子数较低的M&M’态在大气环境中最易体现出其超灵敏探测能力.