正交级联液晶偏振光栅的收发分离结构设计

正交级联液晶偏振光栅可实现光束大范围偏转，在空间激光通信与激光雷达等领域具有广阔的应用前景，其大部分应用领域均需要同时发射激光与接收激光，如何解决发射光与接收光分离的问题尚未见报道。针对这一问题，文中根据1/4波片、1/2波片以及液晶偏振光栅理论推导了线偏振光源经过被动液晶偏振光栅层以及正交级联液晶偏振光栅后偏振态的变化，验证了出射光偏振态与光束偏转角度的可逆性。采用偏振分光棱镜、1/4波片、1/2波片、正交级联液晶偏振光栅等器件设计了一种可实现发射光与接收光偏转与分离的光学结构，构建了测试系统，最后通过测试结果证明了理论的正确性与结构的适用性。

Design of transceiver separation structure for orthogonal cascaded liquid crystal polarization gratings

Orthogonal cascaded liquid crystal polarization grating can realize optical beam large angle-scale deflection, and has broad application prospects in the fields of space laser communication and LiDAR. It need to emit and receive laser at the same time in most application fields, but how to solve the problem of separating emitted light from received light has not been reported. To solve this problem, change of polarization state of outgoing polarization light source after passing through passive liquid crystal polarization grating layer and orthogonal cascade liquid crystal polarization grating was deduced based on the theories of 1/4 wave plate, 1/2 wave plate and liquid crystal deflection grating, the reversibility of the polarization state of the outgoing light and the beam deflection angle was verified. An optical structure which could realize the deflection and separation of transmitted beam and received beam was designed using polarization splitting prism, 1/4 wave plate, 1/2 wave plate and orthogonal cascade liquid crystal polarization grating. A test system was constructed, the test results prove the correctness of the theory and the applicability of the optical structure finally.