Theoretical calculation and experimental study on absorption properties of Yb: YAG crystal applied in thin disk laser

Abstract The thin disk laser is presented as an optimal laser design for the operation of a qua s i-three-level laser active medium. In this paper, according to the Lambert-Bill’s equation, the absorption efficiency with pump laser incident angle and pump pass numbers at room temperature is given for Yb:YAG crystal (Yb 3+ 10%, 0.3 mm thickness). The absorption efficiency is 93.98% for 24 absorption passes with 0.349 rad incident angle. It will be close to 100% when the number of pump passes of Yb: YAG crystal (0.3 mm) is higher than 48, and continuously increasing pump pass numbers no more contribution to optical efficiency. The experimental investigations yield an output power of 41.6 W/1030 nm at 52% slope efficiency at room temperature. At last, the experimental results are analyzed, and methods are promoted to improve the optical efficiency.