Thermal effect of LD end-pumped Nd：YAG crystal with variable thermal conductivity

In order to calculate temperature field and thermal distortion field of laser diode end-pumped Nd:YAG crystal,the temperature thermal model of the crystal was built under the condition of thermal isolation of the end face and constant peripheral temperature.Based on the function of temperature of the Nd:YAG crystal depending upon the thermal conductivity and thermal distortion coefficient,after the thermal model of heat conduction equations were solved by means of the Newton tangent method,the general equations of the temperature field and thermal distortion field of the end-pumped rectangular cross section Nd:YAG crystal with variable thermal conductivity and thermal distortion coefficient were obtained.Then the internal temperature field distribution and thermal distortion field were calculated under different of pump power and pump spot size.Results show that under the condition of 0.01 Nd ion mass fraction,60W pump power and 450μm pump spot radius,the maximum temperature rise on the end face of the Nd:YAG crystal in 3mm×3mm×8mm was 55.7℃,and the maximum thermal distortion was 2.85μm. However,traditionally the thermal conductivity and thermal distortion coefficient were taken as constant,the maximum temperature rise on the end face of the Nd:YAG crystal was 43.4℃and the maximum thermal distortion was 2.84μm.