Abstract:

In the axisymmetrical condition,the temperature distribution of the laser crystal was theoretically analyzed with the pump beam as a standard gauss beam and the heat smoothly distributed,and the thermal focal length is calculated.With different pump power and pump beam radius,the temperature distribution is numerically simulated by ANSYS.The phase distortion of the plane wave through the crystal is numerically calculated.The curve for the variation of the thermal focal length with the radius is plotted.A numerical analysis indicates that the thermal focal length changes with the radius,that the outgoing wave is a non-spherical wave,and that the equivalent concave mirror of thermal lens is aspherical and can not be described by single curvature radius.Finally,a study is made of the effect of pump power and pump beam radius on the thermal focal length.

Key words: diode pumped;solid state lasers;thermal focal length;temperature distribution;phase distortion,aspherical lens