Compact temperature-insensitive high-energy VCSEL side-pumped Nd:YAG laser with a VRM output coupler

A compact temperature-insensitive high-energy Q-switch Nd:YAG laser is demonstrated based on vertical cavity surface emitted laser (VCSEL) side-pumping and a variable reflectivity mirror (VRM) output coupler (OC). With the optimization of the laser parameters, the laser delivers an output energy of 217 mJ operating at pulse repetition rate of 100 Hz with 7 ns pulse width and a peak power of 31 MW. The brightness is estimated to be 10.34×10⁶MW/mm²/sr. The spatial beam exhibits a near-flat-top intensity distribution with good beam quality of M²∼2.3. The temperature stability is measured at full output energy, indicating an energy variation within 1.8% for the temperature range from 15°C to 35°C.