Thermal effects of diode end-pumped Nd:YVO4 solid state laser

Thermal effects of diode end-pumped Nd:YVO4 laser are analyzed in this paper. A laser interferometer is set up to determine the optical path difference (OPD) resulting from thermal effects in crystal under lasing condition. The beam distortions in Nd:YVO4 rod are measured with a He-Ne laser at wavelength of 632.8nm. The changes of interference patterns record the deformation of the rod with increasing pump power. The experimental and theoretical curves of effective thermal focal lengths versus pump power are obtained, and it is found that the theoretical analysis agrees well with experimental measurement. With the analytic results of thermal effects, a optimized resonator is designed to insure that the laser operates in stable mode with an output power of 3.2 W, slope efficiency of 52% and M-2 factor of 1.19.