Polarization characteristic analysis of orthogonal reflectors with a side-scanning galvanometer in a laser communication terminal system

Abstract

An alignment tolerance allocation and alignment method of orthogonal reflectors with high polarization-maintaining characteristics is presented. A geometric optics vector model of orthogonal reflectors is established to derive the propagation vector of the output beam, including pitch angle error of the first mirror, the side-scanning angle of the galvanometer, and rotation angle error of the secondary mirror. The polarization transmission matrix of the orthogonal reflectors is derived based on the 3D polarization ray-tracing algorithm to present the relationship between assembly errors and diattenuation or retardance of the orthogonal reflectors. A calculation example of certain polarization ellipticity error is given to quantitatively distribute the orthogonal mirror assembly error. The optimal side-sway angle selection method of the galvanometer side-sway angle in a laser communication system is presented; further, effective measures to minimize the polarization ellipticity error is put forward.

The Color Improvement of Underwater Images Based on Light Source and Detector

“…The color deviation impacts the reliability and utility in underwater applications [4,5]. There is no doubt that the color improvement of underwater images is significant for underwater applications [6][7][8][9], and the scope of color improvement in underwater images has received considerable attention in recent decades [10,11]. To solve the color deviation of the underwater image, lots of research has been conducted, which can be classified into two categories, including color restoration with prior information of light attenuation, and color enhancement without the information of light attenuation.…”