洛伦兹-高斯光束在梯度折射率介质中的传输

导出了洛伦兹-高斯光束在梯度折射率介质中传输的光场分布,给出了二阶矩定义下的光束半宽度及其变化率的解析表达式,重点分析了梯度折射率系数对洛伦兹-高斯光束传输性能的影响。结果表明,梯度折射率介质中的归一化光强分布和光束半宽度等呈周期性变化,周期为梯度折射率系数的"倍,轴上最大光强出现在半周期处。梯度折射率系数除影响周期性外,对归一化光强分布和光束半宽度无明显影响,但影响光束半宽度变化率。

Propagation of Lorentz-Gaussian beam in gradient-index medium

The optical field of a Lorentz-Gaussian beam propagating in a gradient-index medium is derived. Based on the second-order moment of the intensity distribution, the analytical expressions of the half beam width and its changing rate are also presented. The influence of the gradient-index coefficient on the propagation properties of the Lorentz-Gaussian beam is mainly analyzed. The numerical results show that the variation of the normalized intensity distribution, the half beam width and its changing rate are periodic, and the period is π times the gradient-index coefficient. The maximum on-axis intensity appears at the half period. The gradient-index coefficient nearly doesn’t affect the normalized intensity distribution and the half beam width, but it influences the changing rate of the half beam width.