A Compact Diode End-pumped Passive-Q-switched Nd,Cr:YAG/KTP Laser

We experimentally demonstrate a compact, laser-diode end-pumped passive-Q-switched Nd:YAG/Cr:YAG green laser system, utilizing a KTP crystal for extra-cavity frequency doubling. This system achieves a peak single-pulse energy of 1.84 mJ at the fundamental wavelength of 1064 nm and an maximum single pulse energy of 1.181 mJ at the doubled frequency of 532 nm. The system's frequency doubling conversion efficiency reaches the maximum of 64.1%. The pulse widths for both the 1064 nm and the 532 nm laser are consistently narrow, measured at 2.56 ns and 2.87 ns. The entire laser system, including the frequency doubling component, is remarkably compact, with a total length of 25 mm. This demonstrates that it is feasible to create passive Q-switched pulse lasers with ultra-narrow pulse widths in extremely miniature configurations. Such compact and efficient lasers hold significant promise for practical applications in various engineering fields.