用于光谱合束技术的透射光栅设计与优化

Design and Optimization of Transmission Gratings for Spectral Beam CombiningTechnique

设计并制作了一种亚波长透射光栅,利用该光栅实现了半导体激光阵列光谱合束。基于严格耦合波理论,对光栅占空比、脊高和周期等进行了设计,模拟了不同结构参数对光栅衍射效率的影响,从而实现了光栅衍射效率的优化。理论计算表明,优化后的光栅对940nm激光的-1级衍射效率可达92%。实验结果表明,激光阵列光谱合束后,输出功率为46.2 W,光束质量为3.9mm·mrad。

A sub-wavelength transmission grating is designed and fabricated,which is utilized for the realization of diode laser array spectral beam combining.Based on the strictly coupled wave theory,the grating duty ratio,ridge height and period are designed,the effect of different structural parameters on grating diffraction efficiency is simulated,and thus the optimization of the grating diffraction efficiency is realized.The theoretical calculations show that,for a 940 nm laser,the-1 order diffraction efficiency of the optimized grating can reach 92%.The experimental results show that the output power is 46.2 W and the beam quality is 3.9 mm·mrad after the laser array spectral beam combining.