基于增强型CCD光场高阶相干度的测量

Measurement of High-Order Coherence of Light Field Based on Intensified Charge-Coupled Device

光场的高阶关联特性是揭示光的统计行为的重要特征。采用传统的HBT(Hanbury-Brown and Twiss)实验模型测量多光子高阶关联时,会受到单光子探测器和分束器数量的限制,测量起来比较复杂。提出了一种利用增强型电荷耦合器件(ICCD)快速测量光场高阶关联的方法。通过改变曝光时间和光照强度(计数率)对赝热光场和相干光场的高阶相干度进行测量和分析。结果表明:在适当的条件下,可以确定光场的高阶相干度。当曝光时间为600 ns、计数率为5.12×10^8 s^-1时,实测赝热光场的2阶和3阶相干度分别为g^(2)T(0)=1.79±0.20,g^(3)T(0)=4.94±0.59。对多达4阶的光场相干度进行了测量,该结果能在理论上得到较好的解释。该实验方法有望应用于某些光源的高阶相干性测量和研究方面,对揭示光场的高阶关联行为具有一定意义。

The high-order correlation characteristics of a light field are important features for revealing the statistical behavior of light. When the traditional HBT(Hanbury-Brown and Twiss) experimental model is used to measure the multi-photon high-order correlation, the measurement is complicated because of the limited number of single-photon detectors and splitters. In this study, we propose a fast method to measure the high-order correlation of a light field using an intensified charge-coupled device. The high-order coherence of the pseudothermal and coherent light fields can be measured and analyzed by varying the exposure time and light intensity(counting rate). The results demonstrate that the high-order coherence of a light field can be determined under appropriate conditions. When the exposure time is approximately 600 ns and the counting rate is 5.12×10^8 s^-1, the measured second-order and third-order coherences of the pseudothermal light fields are g^(2)T(0)=1.79±0.20 and g^(3)T(0)=4.94±0.59, respectively. Note that the coherence of up to four orders has been measured and that the results can be theoretically explained. We expect that this method can be applied for measuring and studying the high-order coherence of some light sources. Furthermore, we believe that the proposed method will significantly contribute to revealing the high-order correlations of the light fields.