This paper presents a new optical system for detecting light signals associated with the change in incoming photon number. The system employs quantum correlation of photon pairs created via spontaneous parametric down-conversion (SPDC). The signal, if present, will perturb the flux of the incident photon stream. The perturbed photon stream is first projected through a birefringent crystal where SPDC occurs, converting a single high-energy photon into a pair of low-energy photons. The photons in each pair eventually arrive at separate detectors. By examining the biphoton correlation using the probability distribution of the photons at the detectors, which varies depending on the displacement of the main “pump” photon stream and the change in the number of photons, the small optical displacement of the photon stream and its variance can be determined. The change in incident photon number, in other words, the presence of light signal does not influence the average of the measured optical displacement values. Nevertheless, the change in optical displacement measurement variance when the number of incident photons has changed detects the light signal. This optical setup enables the detection of light signals with low noise and remarkably high precision and sensitivity using quantum correlation. The proposed technique has potential application for axion-like particle search in experimental high energy physics.

本文提出了一种新的光学系统，用于检测与入射光子数变化相关的光信号。该系统利用通过自发参数下转换（SPDC）创建的光子对的量子相关性。信号（如果存在）将干扰入射光子流的通量。首先将扰动的光子流投射通过SPDC发生的双折射晶体，将单个高能光子转换为一对低能光子。每对中的光子最终到达单独的检测器。通过使用检测器上光子的概率分布检查双光子相关性，该概率随主要“泵浦”光子流的位移和光子数量的变化而变化，可以确定光子流的较小光学位移及其方差。入射光子数的变化，换句话说，光信号的存在不影响测得的光学位移值的平均值。然而，当入射光子数改变时，光学位移测量方差的改变检测到光信号。这种光学设置可以使用量子相关性检测低噪声，高精度和高灵敏度的光信号。所提出的技术在实验高能物理中具有类似轴突粒子搜索的潜在应用。当入射光子数改变时，光学位移测量方差的变化检测到光信号。这种光学设置可以使用量子相关性检测低噪声，高精度和高灵敏度的光信号。所提出的技术在实验高能物理中具有类似轴突粒子搜索的潜在应用。当入射光子数改变时，光学位移测量方差的变化检测到光信号。这种光学设置可以使用量子相关性检测低噪声，高精度和高灵敏度的光信号。所提出的技术在实验高能物理中具有类似轴突粒子搜索的潜在应用。