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运用边界元素法把圆形高斯镜平凹腔的自再现模的衍射积分方程转化为有限阶矩阵方程。计算了谐振腔在理想情况和高斯反射率平面输出镜倾斜情况下基模的场强分布、相位分布和本征值。研究表明,腔镜倾斜使激光场模式分布沿发生倾斜的方向向镜边缘偏移,而且在腔镜倾斜较严重时模式分布发生畸变,不再是对称的拉盖尔-高斯基模分布。基模本征值随倾斜角增大而变小,光束远场分布变差。减小高斯分布反射率的膜斑半径,则能减弱因倾斜引起的模式畸变。
The boundary element method is used to transform the diffraction integral equation of the self-recurrence mode of the circular concave cavity of a flat-faced Gaussian mirror into a finite-order matrix equation. The field strength distribution, phase distribution and eigenvalue of the fundamental mode in the ideal case and the tilt of the output mirror with Gaussian reflectivity are calculated. The results show that the lasing angle mode shifts the laser mode distribution to the edge of the mirror along the tilt direction, and the mode distribution distorts when the mirror tilt is more serious than the symmetrical Laguerre-Gaussian mode distribution. The eigenvalue of the fundamental mode becomes smaller as the tilt angle increases, and the beam far-field distribution becomes worse. Reducing the speckle radius of Gaussian distribution reflectivity reduces mode distortion due to tilt.