Influence of KTP length on the performance intracavity frequency doubled diode-pumped Nd:YVO4 lasers

We demonstrate an experimental study of the influence of potassium titanyl phosphate (KTP) length on the performance of intracavity frequency-doubled diode-pumped Nd:YVO/sub 4/ lasers operating in continuous-wave (CW) mode and passive Q-switch mode. Theoretical and experimental results show that the optimum KTP length for CW mode is determined by the nonlinear coupling and walkoff effect and the highest optical conversion efficiency in CW mode is nearly 30% with a 10-mm KTP. On the other hand, a 2-mm KTP crystal, which is sufficient for efficient internal second-harmonic generation in a passive Q-switch mode, yield the highest peak green power of 240-W.