用快速傅里叶变换法分析超高斯反射镜腔的光场分布

常规非稳腔由于输出耦合镜硬边光阑的衍射效应而影响了激光输出。使用非均匀反射镜，可以起到软边光阑的作用，改善了输出光束的光场分布特性。高斯分布反射镜已经被广泛应用，超高斯分布反射镜的提出是对非均匀反射腔的一大改进。快速傅里叶变换(FFT)方法是计算激光腔光场分布的一种方便快捷的方法，利用快速傅里叶变换方法分析了超高斯反射镜腔的腔内三维光场分布情况，并模拟了热透镜焦距变化时腔内光场分布的变化。然后分别在空腔和考虑热透镜效应的情况下对输出光束的光场分布进行了理论模拟，并讨论了热透镜效应对输出光场分布的影响。

Analysing the Light Intensity Distribution of Super-Gaussian Mirror Resonator by Fast Fourier-Transform

For the conventional unstable resonator, the output laser is deteriorated by the hard edge diaphragm diffraction. Using variable reflective mirror, as a soft edge diaphragm, the intensity distributions of output laser are improved. Gaussian mirror has been used widely, and the super Gaussian mirror is a development for variable reflective mirror. The fast Fourier transform (FFT) algorithm is a convenient method for simulating the intensity distribution of resonator. In this paper, the three dimensional intracavity distribution of super Gaussian mirror resonator is analyzed, and the intensity distributions are simulated when the thermal focal length changes. Then the output intensity distributions are simulated with or without considering the thermal lens effect. And the influence of the thermal lens effect is discussed.