机载光学平台平均流场气动光学效应研究

使用选区电子衍射软件模拟机载光学平台绕流流场,根据绕流流场定量研究了气动光学平均流场效应的性质及其随激光传输角度的变化。发现平均流场气动光学效应引起的波前畸变主要是低阶像差,整体倾斜占比约92%,整体倾斜、离焦和像散三项总和占比平均值99%以上;随传输方向变化,波前像差均方根值以及波前性质有显著不同:对于不同的传输方向,光程差(OPD)均方根值(RMS)的变化范围从0.13～1.20μm,光轴偏向角的变化范围从1～12μrad。去倾斜后的波前像差引起的光束质量因子β值,对所有方向的统计平均值为1.8;校正了离焦和像散后,光束质量因子β值的平均值为1.16。光束质量因子β值随口径增加而增加,无自适应光学校正时变化规律接近线性。

Simulation on Mean Flow-Field Aero-Optic Effect of Airborne Optical Platform

The simulation of the mean flow over airborne laser fairing as well as its aeroptic analysis with selected area electron diffraction software is presented. The simulation reveals that the aero-optic effect with respect to the mean flow field strongly depends on the beam direction: along different beam propagation directions, the root mean square of optical path difference varies between 0.13~1.20 μm, and tilt angle of beam axis varies between 1~12 μrad. Furthermore, the wave-front distortion caused by mean flow-field aeroptic effect is mainly low-order effect: the ratio of tilt to the aberration is about 92%, and the ratio of tilt, defocussing and astigmatism is about 99%. The average of beam quality factor β over all directions caused by no-tilt wave-front aberration is 1.8; when defocussing and astigmatism is corrected, the average of beam quality factor β is 1.16. The beam quality factor β caused by no-tilt aberration increases with the increment of beam radius as a nearly linear manner.