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为研究激光经运动漫反射目标后光场统计的特性,结合多像素光子计数器(MPPC)的光子统计模型,并利用光子统计二阶矩和均值,得到描述光子数波动的Fano因子。然后对该因子进行曲线拟合,得到衡量赝热光场光子分布杂乱程度的热模数μ,同时可得衡量探测系统增益系数γ和串扰概率ε的组合参数B。实验结果表明,漫反射目标旋转驱动电压从20 mV逐渐变化到1280 mV,回波光子热模数μ从289增加到1229,且随着电压增大,热模数增长速率逐渐减缓。由于探测器增益γ在实验过程中保持恒定,B参数的变化直接反映探测器像素之间串扰概率的变化,结果表明漫反射目标转速增加,MPPC串扰概率ε减小,通过Fano因子的曲线拟合只给出串扰概率的定性描述,得不到增益系数的相关信息。只有对光子统计三阶矩进行分析,才能获得探测器增益及串扰概率的定量描述。
In order to study the statistical properties of the laser field after diffuse reflection, a Fano factor describing the fluctuation of photon number is obtained by combining the photon statistical model of multi-pixel photon counter (MPPC) with the second moment and mean of photon. Then, the factor is curve fitted to get the thermal modulus μ which can measure the degree of disorder of photon distribution in the pseudo-thermal field and the combination parameter B which can measure the gain coefficient γ of the detection system and the crosstalk probability ε. The experimental results show that the rotational driving voltage of diffuse reflection target gradually changes from 20 mV to 1280 mV, and the photon thermal modulus μ of the echo increases from 289 to 1229. With the increase of voltage, the rate of increase of thermal modulus slows down. As the detector gain γ is kept constant during the experiment, the change of B parameter directly reflects the change of the crosstalk probability between detector pixels. The result shows that the diffuse reflection target speed increases and the MPPC crosstalk probability ε decreases. The Fano factor curve fitting Only given a qualitative description of the crosstalk probability, gain-related information can not be obtained. Only by analyzing the third moment of photon statistics can we obtain a quantitative description of the probability of detector gain and crosstalk.