道威棱镜的偏振特性及偏振补偿研究

为了避免机载光电吊舱中共口径光学系统内部由于道威棱镜旋转引起的激光照射脉冲偏振态的变化,利用琼斯矩阵对道威棱镜的偏振特性与四分之一波片、半波片补偿道威棱镜旋转引起的激光脉冲偏振态变化进行了理论分析和实验验证。结果表明:线偏振的激光脉冲通过旋转一定角度的道威棱镜时,激光脉冲偏振态变为椭圆偏振,偏振态发生变化;而激光脉冲首先通过旋转一定角度的四分之一波片与半波片时,可使通过道威棱镜系统的激光脉冲偏振态保持不变,且两波片旋转角度与道威棱镜旋转角度之间存在一种非线性关系。采用偏振补偿方法可有效避免机载共口径光学系统中道威棱镜引起的激光脉冲偏振态变化,提高激光脉冲能量利用率,降低激光脉冲后向散射抑制难度。

Polarization properties and polarization compensation of Dove prism

In order to avoid the polarization changes of the irradiation laser pulse, caused by the rotation of Dove prism in the co-aperture optical system of airborne electro-optical pod, the polarization properties of the Dove prism and the compensation of the polarization changes of laser pulse are theoretically analyzed by Jones matrix, and they were also experimentally verified.In the compensation of polarization, a quarter-wave plate and a half wave plate are used.The results show that, when the linearly polarized laser pulse passes through the Dove prism that rotated an angle, the polarization state of the laser pulse becomes elliptically polarized.Obviously, the polarization state has changed.Moreover, when the laser pulse passes through a quarter-wave plate and a half wave plate that rotated a certain angle firstly, the output laser pulse polarization states at Dove prism system remain unchanged, and there is a nonlinear relationship between the two wave plates' rotation angles and Dove prism's rotation angle.Therefore, this polarization compensation method can effectively avoid the laser pulse polarization change caused by Dove prism rotation in co-aperture optical system of airborne electro-optical pod.Consequently, the utilization of the laser pulse energy is improved and the difficulty of suppressing the backscattering of laser pulse is decreased.