通过实验观测了湍流大气中光束准直传输时光束横截面上不同面积内的光强起伏特征。采用相对光强起伏方差与孔径平滑因子描述不同面积内的光强起伏特征并比较了不同湍流条件和不同面积内相对光强起伏方差的概率分布密度。实验结果表明, 在该实验条件下明显出现孔径平滑效应时对应接收面积呈现湍流越强接收面积越小的规律; 不同接收面积内相对光强起伏方差概率分布密度可以用对数高斯分布近似, 不同接收面积和湍流强度下近似程度不同; 采用偏斜度和陡峭度来描述接收面积不同和湍流强度不同时概率分布密度与对数高斯分布的偏差并比较了拟合曲线特征的变化。同时初步比较了连续光与脉冲光相对光强起伏方差概率分布的异同。

Property of intensity fluctuation over different receiving aperture for collimated beam propagation in atmosphere is got by experimental method. Using normalized variance of intensity fluctuation and aperture averaging factor the property of intensity fluctuation over different receiving aperture is described and the probability distribution of normalized variance of intensity fluctuation measured with different aperture sizes under different atmosphere conditions is compared. Experimental results show that while turbulent level becomes larger, the receiving area corresponding to aperture averaging effect appears obviously becomes smaller. The probability distribution corresponding different receiving area can be represented by Log-Gauss distribution. Skewness, kurtosis and the feature of Gauss fitted data calculated under experimental conditions are compared. The similarities and differences between the relative intensity fluctuation variance probability distribution of the continuous-wave laser and one of pulsed laser are also compared.