干涉法测量中的信噪比

本文根据现代随机介质中波的传播理论,从二阶互相干函数出发导出了干涉图信噪比的分析表达式,对不同情况下的结果作了讨论,表明信噪比决定于光束的波长与宽度,传播距离和湍流强度等因素。在一定条件下信噪比将趋向于一个常数,可以用强度起伏的饱和效应来解释这个现象。

The signal-to-noise ratio in interference measurement

Upon the basis of modern wave propagation theory in a random medium,the analytical expressions of the interferogram's signal-to-noise ratio are derived in this paper,starting off with second-order mutual coherence function.Several results for different condition are discussed.These show that the signal-tonoise ratio is dependent on the wave length,width of the wave beam,propagating distance,turbulent intensity,and et cetera.Calculations indicate that the correlation of the intensity fluctuation plaies an important role and the focused beam has not any predominance in comparison with the collimated beam.The interferogram's signal-to-noise ratio will tend towards a constant under a certain condition,which can be interpreted by the saturation effect of optical intensity fluctuation.