相干合成子光束一致性检测研究

分析了激光相干合成装置及其光路调整要求，提出利用剪切干涉检测合成光路中子光束一致性的方法。分析剪切干涉原理，建立了剪切板干涉物理模型，以相干合成中两路矩形光束拼接组束为例，数值模拟并研究了子光束的整体倾斜、离焦所对应的剪切干涉条纹，得到了条纹图像与子光束光轴误差、离焦误差之间的对应关系，用于相干合成光路中子光束光轴和发散角误差的判断。光轴倾斜大于5 rad时，可以直接观察互干涉和自干涉条纹变化，发散角在大于10 rad时，干涉条纹变化明显。此外，剪切干涉的自干涉条纹平移可用来检测子光束间的活塞误差，可作为光束拼接相干合成中闭环相位检测和控制的手段。

Uniform testing of beams in laser coherent beam combination

The coherent-beam-combining device and the requirements for optical-path adjustment were analyzed. Detecting the coherence of combined beams using the shearing interferometer was proposed. According to the principle of shearing interferometer, the physical model was constructed. Taking two coherent rectangular beams rectangling as an example, numerical simulation was studied on the relationship between the errors and the fringes. This method was visual, simple and precise. The results show that the existence of phase piston can be tested by shearing interferometer. So shearing interferometer could be a new method of detecting phase errors for coherent beam combination.