High-average-power thin-tapered-rod ultrafast laser amplifier with gradient-doped Yb:YAG crystal

Gradient doping in thin-rod and thin-tapered-rod active elements was proposed and implemented. Thermal and laser processes in such elements were studied theoretically and experimentally. It was shown that the use of tapered active elements with gradient doping enables simultaneous gain enhancement and reduction of the temperature of the active medium, thereby increasing amplification efficiency and improving beam quality. An amplifier with unique cumulative parameters: an average power of 150 W and an amplification efficiency of 35% with beam quality parameter M2 = 1.62 x 1.53 was developed.(c) 2023 Optica Publishing Group