研究红外波段沙尘的散射特性对自由空间光通信(FSO)具有重要的理论意义。针对FSO常用的几个红外波长,采用Mie理论对激光在不同沙尘粒径下的散射特性进行了分析;基于粒子尺寸的对数正态分布模型,计算了沙尘条件下红外波段(0.76~10.6μm)激光的传输衰减率。结果表明:在沙尘条件下,7.4~8.0μm这一波段附近的传输衰减最小,并且明显低于其他波段。因此,可以选用7.4~8.0μm这一波段的激光进行沙尘条件下的激光通信,其传输性能会明显优于其他波段。最后,以波长1.064μm为例,分析了“能见度”随粒子浓度的变化关系,并与蒙特卡罗方法的计算结果进行了比较。
Research on scattering characteristics of sand and dust in the infrared waveband has important theoretical significance for Free Space Optical (FSO) communication. According to some infrared wavelength commonly used in FSO, its scattering characteristics in different particle sizes of sand and dust were analyzed by Mie theory; based on log-normal distribution model of particle size, the attenuation coefficient of laser in waveband 0.76-10.6 μm were calculated under the condition of sand and dust. The results show that: the transmission attenuation near waveband 7.4-8.0 μm are minimum under the condition of sand and dust, and it's significantly lower than that in other wavebands. Therefore, the laser in waveband 7.4-8.0 μm should be chosen to be used in FSO under the condition of sand and dust, for that its transmission performance will be obviously better than that in other wavebands. At last, take wavelength 1.064 μm as an example, the "visibility" with the change of particle concentration was analyzed, and the result was compared with that by Monte Carlo method.