Investigation of anisotropic thermal lens effect in a dual-polarized Nd:YLF laser.

The anisotropic thermal lens effect of a dual-polarization Nd:YLF laser is experimentally investigated by measuring the transverse beat frequency between TEM0,0 and TEM1,0 modes in the self-pulsing operation, and focal lengths of thermal lensing for both polarizations can be accurately determined. The focal length of the thermal lens for π polarization was observed to be negative and varies from -1.1 to -0.5m for the absorbed pump power increasing from 1.7 to 3.8 W. For σ polarization, the focal length of the thermal lens was determined to be positive and varies from 1.2 to 0.9 m for the absorbed pump power increasing from 8.4 to 10.9 W. The sensitivity factors of the thermal lens for both polarizations were evaluated to be Mπ=-0.54m-1/W and Mσ=0.1m-1/W, respectively.