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High-power structured beams with the transverse morphologies as the Lissajous figures are generated by an Nd:YVO4 laser under two-dimensional off-axis pumping. By fine-tuning the cavity length in the neighborhood around the condition of longitudinal-transverse coupling, different cases of accidental degeneracies from the intracavity astigmatism are achieved to lead the output emission to be various Lissajous modes with different transverse frequency ratios. The generated Lissajous modes reveals good power performance with slope efficiency up to 47% and optical-to-optical conversion efficiency to be higher than 37.5% at a pump power of 16 W. Moreover, by applying beam transformation via a single-lens astigmatic mode converter, the generated Lissajous modes are further converted into structured vortex beams with transverse patterns localized on the trochoidal curves. The transformed trochoidal vortex beams are confirmed to preserve well-defined mode structures even when the average output power has been scaled up to be higher than 4 W.

Beam degradation of Lissajous structured modes induced by thermal effects was explored by a high-power diode-pumped YVO4 laser. Experimental results reveal that the generated Lissajous patterns will deform significantly during power scaling when using a higher Nd-doping level gain crystal due to stronger thermal loading. By further performing astigmatic mode conversion, the corresponding trochoidal beams are confirmed to be greatly influenced by the thermal aberration of the gain medium.

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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.