非傍轴双曲正弦高斯光束质量因子M2的研究

在标量光场角谱衍射理论的基础上,应用精确光强定义下的非傍轴标量光束的光强二阶矩理论,计算了非傍轴双曲正弦高斯光束的束腰半径、远场发散角、质量因子,并与傍轴双曲正弦高斯光束的质量因子进行了比较研究。数值计算表明,当双曲正弦高斯光束束腰半径较大时,传统光强定义下的光强二阶矩理论近似成立,傍轴与非傍轴理论计算的光束质量因子变化规律完全相同;束腰半径较小时,傍轴理论计算的结果有较大误差,必须采用精确光强定义下的非傍轴光束质量因子的定义作修正。

Study on the beam quality factor of sinh-Gaussian(ShG) beams

Based on the angular spectrum representation and the theory of the second intensity moment of non-paraxial scalar beam,the beam waist radius,the far-field divergence angle and the beam quality factor of non-paraxial scalar sinh-Gaussian(ShG) beams were calculated.Compared with the beam quality factor of paraxial scalar sinh-Gaussian (ShG) beams,some new results were obtained.When the beam waist radius is relatively large,the theoretical calculations for the beam quality factor of paraxial and non-paraxial scalar sinh-Gaussian(ShG) beams change in the same way and the theory of the traditional second intensity moment of scalar light field is a valid approximation; when the beam waist radius is very small,they have a great difference and the theory of the second intensity moment of non-paraxial scalar beam must be used.