散斑可见度光谱法中的相干因子

Coherence factor in speckle visibility spectroscopy

散斑可见度光谱法是近年来兴起的研究密集颗粒流运动的新方法。针对散斑可见度光谱法测取颗粒温度的实验中,如何消除相干因子测量过程中的误差进行了研究。比较了静态散斑对比度以及散斑对比度系数的计算方法以及消除相干因子的方法,实验测量结果表明,由散斑对比度系数消除相干因子的方法能最大程度地保留测量准确度。该方法能够消除由环境不同及激光不稳定所带来的误差,使得同类实验具有更好的对比性。同时给出了计算量较大导致的时间分辨率较低这一问题的解决方法。

Based on the speckle visibility spectroscopy that is developed to study the dense particle flow in recent years,we discuss and compare the different methods to determine granular temperature through coherence parameterβ,and draw a conclusion that using the method of calculating speckle visibility ratio to eliminate coherence parameterβcan reduce the measurement error to the greatest extent.It makes better compared results from various experimental conditions because of elimination of the environmental error.Furthermore,we provide a solution to keep the high time-resolution,which is proved by experiments.