Characterizing thermally-induced beam deformation of Lissajous laser modes in a high-power end-pumped Nd:YVO4 laser

Deformed beam structures of Lissajous transverse patterns induced under high-power pumping were explored in an off-axis pumped Nd:YVO4 Laser within a degenerate cavity configuration. Experimental results show that beam structure variations including elongation, rotation and vagueness will occur with increasing pump power. Considering crystal axis rotation of gain medium induced by the inhomogeneous temperature gradient under high-power pumping, the derived resonant wave function of the spherical cavity can well reconstruct the experimental observation to further give an explicit relation between the tilt angle and aspect ratio of Lissajous patterns. It is believed that this finding can provide helpful information for the research on high-power structured light.