碘激光的大气衰减特性

碘激光波长处在大气微窗口，水汽分子的吸收是碘激光在大气中传输时衰减的主要原因。利用HITRAN数据库，计算了碘激光波长模式的大气衰减情况。利用高分辨串光谱实验系统，获得了1．315μm附近的谱线参量。在我国，由南向北，由夏到冬，水汽浓度逐渐减少，水汽分子的吸收率递减。碘激光有6条超精细谱线，单一最强线频率的碘激光的大气分子吸收比多谱线的碘激光小，更有利于大气传输。在中纬度夏季，单一最强线垂直向上全程的大气分子吸收率与多谱线碘激光水平传输1km相当，为9．0％。碘激光垂直向上传输比海平面水平传输受大气影响小。

Atmospheric Attenuation of the Iodine Lasers

The wavelengths of iodine laser are in an atmospheric micro-window. The absorption by water vapor is its main absorption besides aerosol in this region. The absorption coefficients and transmittance of several model atmospheres are calculated. In China, from south to north, from summer to winter, the water vapor density is decreasing, and the iodine laser beam absorption rate by water vapor is decreasing as well. It is better that an iodine laser beam transmits vertically upwards than horizontal flatly on the sea level. The absorption of an iodine laser beam with single main line is less than that with multi-lines.