Causes of high-order thermal aberrations and their influence on beam quality in end-pumped Nd:YVO4 crystals

The causes of high-order aberrations, such as triangular astigmatism and coma, are investigated in end-pumped Nd:YVO 4 crystals. A high-resolution infrared thermal camera is utilized to obtain the temperature distribution on the end face of Nd:YVO 4 crystals with high-power pumping. It is demonstrated that errors in optical path adjustment and non-uniform heat dissipation would produce additional high-order aberrations, leading to a deterioration in beam quality. The required operating conditions and tolerance ranges for the precise optical path are provided. The experimental results are consistent with the theoretical analysis.