激光大气闪烁的高频谱特性

High-frequency spectrum behavior of laser scintillation in turbulent atmosphere

采用三波长闪烁仪进行了大气边界层的光传输实验,结果表明:在相同的传播条件下,非平面波激光大气闪烁功率谱的高频部分与波长存在着一定的关系,功率谱无标度区间的斜率即标度指数是一个与湍流强度、波长等因素有关的函数,在满足弱起伏的条件下,标度指数一般与波长呈负相关,波长愈长则标度指数愈小,频谱下降的趋势愈快;波长愈短则标度指数愈大,频谱下降的趋势愈慢。

Field experiments were performed upon the laser beam propagation using a three-wavelength scintillometer in the maritime atmospheric boundary layer. The results show that the high-frequency spectrum behavior has something to do with the wavelength. The slope of the scaling region （or the scaling exponent） is anti-correlated with the wavelength, that is to say, the longer the wavelength is, the less the scaling exponent is, and vice versa.