谱合成光束特性的模拟分析

建立了光束谱合成的传输模型.应用光线追迹方法，将闪耀光栅引起的相位变化用槽间光程差和槽内光程差来表示，建立了光束倾斜入射到光栅时相位变化的计算模型.利用衍射积分方法，给出了阵列光源各子光束经谱合成系统后输出光场的解析表达式.依据光束非相干叠加的原理，计算得到合成光束的光强分布.在此基础上，利用强度二阶矩方法，分别计算了阵列光束和合成光束的M²因子，并定量分析了谱合成系统参数对合成光束特性的影响.研究结果表明：通过谱合成系统合成光束的M²关键词： 光束谱合成 阵列光源 闪耀光栅 光束质量

Analysis of the property of the beam after spectral beam combining

A propagation model for spectral beam combining is set up in this paper. First, using ray tracing method, the phase change induced by the blazed grating is expressed with the optical path differences in the groove and between grooves and the calculation model for the phase change of the beam obliquely incident on the grating is constructed. Then, using the diffraction integral method and the principle of incoherent superposition, the analytical expression for the output field of each emitter after passing through the spectral beam combining system is given and the intensity distribution of combined beam is calculated. Finally, using to the intensity second-order moments method, the M²-factors of the array beam and the combined beam are calculated and the effect of the system parameters on the characteristics of the combined beam is analyzed quantitatively. The results show that the M²-factor of the combined beam after passing through the spectral beam combining system remains almost the same as that of an individual emitter. The spacing of center wavelength between each emitter decreases with the increasing focal length of the transforming lens, resulting in the narrower spectrum width of the combined beam. The encapsulation error of the array elements has relatively little effect on the intensity distribution of the combined beam, whereas the position error of the array source has relatively greater effect on the combined beam.