Temperature dependence of the absorption coefficient of V:YAG saturable absorber

The V:YAG saturable absorber enables passive Q-switching in Nd-based lasers, particularly in the 1.0–1.4μm spectral range, making them valuable for applications in medicine and LIDAR systems. The absorption coefficient of V:YAG is a key parameter in Q-switching, affecting intracavity losses and pulse characteristics. However, its temperature dependence can influence laser performance. This study investigates the absorption coefficient of a disc-shaped V:YAG crystal (4mm thick, 10mm diameter) in the spectral region around 1.3μm at temperatures from 220 to 380K. Results show a decrease in absorption up to 1369nm, with the largest drop at 1281nm. Beyond this range, absorption increases with temperature, peaking at 1409nm. These findings enhance the understanding of V:YAG’s thermal behavior, aiding in the development of stable passively Q-switched lasers. The impact of temperature-induced V:YAG changes was analysed in microchip lasers operating at 1.34 and 1.44μm.