康丁, 王春阳, 王子硕, 王增, 郑青泉. 基于样条插值的液晶空间光调制器衍射效率优化方法研究[J]. 红外与激光工程, 2022, 51(9): 20210827. DOI: 10.3788/IRLA20210827
引用本文: 康丁, 王春阳, 王子硕, 王增, 郑青泉. 基于样条插值的液晶空间光调制器衍射效率优化方法研究[J]. 红外与激光工程, 2022, 51(9): 20210827. DOI: 10.3788/IRLA20210827
Kang Ding, Wang Chunyang, Wang Zishuo, Wang Zeng, Zheng Qingquan. Optimization method of diffraction efficiency of liquid crystal spatial light modulator based on spline interpolation[J]. Infrared and Laser Engineering, 2022, 51(9): 20210827. DOI: 10.3788/IRLA20210827
Citation: Kang Ding, Wang Chunyang, Wang Zishuo, Wang Zeng, Zheng Qingquan. Optimization method of diffraction efficiency of liquid crystal spatial light modulator based on spline interpolation[J]. Infrared and Laser Engineering, 2022, 51(9): 20210827. DOI: 10.3788/IRLA20210827

基于样条插值的液晶空间光调制器衍射效率优化方法研究

Optimization method of diffraction efficiency of liquid crystal spatial light modulator based on spline interpolation

  • 摘要: 针对液晶空间光调制器阵元间相位调制量偏差降低光束衍射效率的问题,提出基于样条插值的液晶空间光调制器衍射效率优化方法。依据泰曼-格林干涉原理,搭建了相位调制系统。对调制器加载阶梯变化的灰度图,通过计算干涉条纹移动量,绘制液晶空间光调制器相位调制曲线。采用三次样条反插值法对相位调制曲线进行校正,实现对相位调制量的相位补偿。搭建液晶空间光调制器衍射效率测试系统,对所提优化方法进行实验验证,并与随机梯度下降法进行了对比。结果表明:当光束偏转角度为1.56°、0.78°、0.39°、0.19°时,文中所提方法提高了30%~40%的光束衍射效率,相较于随机并行梯度下降法,衍射效率提高了2%~8%。该方法有效抑制了栅瓣能量,提升了主瓣光束衍射效率,克服了随机并行梯度下降法迭代次数多,优化速度慢,易陷入局部最优的缺点。

     

    Abstract: To reduce the diffraction efficiency of liquid crystal spatial light modulator, an optimization method of diffraction efficiency of liquid crystal spatial light modulator based on spline interpolation is proposed. According to Tyman-Green interference principle, the phase modulation system is built. Loading on the modulator with a grayscale map of step change, the phase modulation curve of liquid crystal spatial light modulator is drawn by calculating the movement of interference fringes. The cubic spline inverse interpolation method is used to correct the phase modulation curve and to realize the compensation of the phase modulation amount. The diffraction efficiency test system of liquid crystal spatial light modulator is set up, and the experimental verification of the proposed optimization method is carried out and compared with the stochastic gradient descent method. The results show that when the beam deflection angle is 1.56°, 0.78°, 0.39° and 0.19°, the diffraction efficiency of the proposed method can increase by 30% to 40%. Compared with the stochastic parallel gradient descent method, the diffraction efficiency increases by 2%-8%. This method can effectively suppress the gate lobe energy, improve the diffraction efficiency of the main lobe beam, and overcome the disadvantages of the stochastic parallel gradient descent method, such as a number of iterations, slow optimization speed, and easy to fall into local optimal.

     

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