Wang Zishuo, Wang Chunyang, Liang Shuning, Liu Xuelian
Opt Express. 2022 Feb 28;30(5):7319-7331. doi: 10.1364/OE.452397.
The non-mechanical beam steering system is composed of multiple liquid crystal polarization gratings (LCPGs) cascaded by binary or ternary technologies. However, cascading multiple LCPGs cause the beam from one LCPG to obliquely enter the subsequent LCPGs, changing their diffraction efficiency and working voltage at different steering angles. This paper uses the elastic continuum theory of liquid crystals to simulate the tilt angle of liquid crystal molecules under different voltages. The transmission process of the beam in the system at oblique incidence is described with an extended Jones matrix, and the highest diffraction efficiency and working voltage of each LCPG at different steering angles are calculated using vector diffraction theory. It is convenient to calibrate the LCPGs' working voltage and analyze the system's diffraction characteristics. In addition, we used an improved binary cascade technology to design a LCPG non-mechanical beam steering system with a steering angle of ±10° and an angular resolution of 0.67°. Compared with binary cascade, this technology can effectively reduce the number of cascaded devices and increase the system throughput under the same maximum beam steering angle and angular resolution.
非机械光束转向系统由采用二元或三元技术级联的多个液晶偏振光栅（LCPG）组成。然而，多个LCPG级联会使来自一个LCPG的光束倾斜进入后续的LCPG，从而在不同的转向角度改变它们的衍射效率和工作电压。本文利用液晶的弹性连续体理论来模拟不同电压下液晶分子的倾斜角度。用扩展琼斯矩阵描述光束在系统中斜入射时的传输过程，并利用矢量衍射理论计算每个LCPG在不同转向角度下的最高衍射效率和工作电压。这便于校准LCPG的工作电压并分析系统的衍射特性。此外，我们采用改进的二元级联技术设计了一种转向角为±10°、角分辨率为0.67°的LCPG非机械光束转向系统。与二元级联相比，该技术在相同的最大光束转向角和角分辨率下，能有效减少级联器件的数量并提高系统吞吐量。
