样品位置和光腰半径变化对折射型光限幅器性能的影响

Effects of the medium location and the beam-waistradius on the operating performances of therefractive optical limiting devices

本文以衍射理论为基础,通过数值计算,研究了以自聚焦和自散焦为基础的非线性折射型光限幅器的光限幅特性,探讨了样品盒的安装位置和入射光束腰斑半径的变化对折射型光限幅器工作性能的影响。结果表明:折射型光限幅器的光限幅特性曲线随激光输入功率的增加是衰减振荡的。光束聚焦差时,样品盒宜靠近焦面安装;光束聚焦好时,样品盒可稍远离焦面安装。对于自聚焦(自散焦)型非线性光限幅器,当样品盒安装在焦点左面(右边)半个瑞利范围内某位置时,透过率最小,限幅器可获得最佳限幅效果。

On the basis of the Gaussian beam assumption and the diffraction theory of light, we studied the optical limiting properties of the refractive optical limiting devices based on self-focusing and self-defocusing, and examined the effects of the location of the nonlinear medium and the waist size of the incident Gaussian beam on the operating performances of the refractive optical limiters. Our numerical results show that the optical limiting curves of the refractive optical limiters assume a vibrating decaying waveform. If the convergence of the incident beam is poor, the distance between the sample cell and the focal plane must be slightly smaller, but if the convergence of the beam is good, the distance between the cell and the focal plane must be slightly larger. For a self-focusing (self-defocusing) optical limiter, the optimum optical limiting effect can be obtained when the nonlinear medium is positioned at a certain location within half a Rayleigh range in the left (right) side of the focal plane.