Unexpected temperature rise in end-pumped Nd3+:YAG composite slab laser

Unexpected temperature rise is observed in end-pumped YAG–Nd3+:YAG–YAG slab laser experimentally. The measured optical absorption spectrum of undoped YAG in 780–830 nm indicates an absorption coefficient of 0.015 cm−1 at 808 nm. The influence of the weak absorption on temperature distribution in end-pumped composite slabs is analyzed numerically and a good agreement with infrared measurement is achieved. The results of finite element analysis show that longer heat sinks and wider slabs bring lower temperature.

► An unexpected high temperature is observed experimentally in the undoped YAG end caps. ► The absorption spectrum of undoped YAG in 780–830 nm is measured. ► The weak absorption of undoped YAG cannot always be ignored, especially in high-power operation. ► High quality laser crystal is crucial to high-power solid-state lasers. ► Longer heat sink and wider slab can bring lower end temperature in composite slab.