두 개의 Yb:YAG 디스크 레이저 모듈로 구성된 레이저 출력 특성 연구

Abstract

In this thesis, we propose the new laser resonator composed of two longitudinally pumped Yb:YAG disk laser modules and investigate its output characteristics. To optimize the output of the new designed laser, we firstly design a laser resonator with single Yb:YAG disk laser module and analyze its output characteristics. The designed laser with single Yb:YAG disk laser module has a slope efficiency of 17∼19% and a beam quality () of 1.10∼1.40. Also by coupling a semiconductor saturable absorber mirror (SESAM) to the designed laser with single Yb:YAG disk laser module, we generate mode-locked pulses. The mode-locked pulses has an average power of 0.68 W at the pump power of 17.8 W, the pulse width of less than 262 ps and its repetition rate of 37 MHz. To increase output power of the designed laser resonator with single longitudinally pumped Yb:YAG disk laser module, we insert an additional Yb:YAG disk laser module inside the resonator. The two Yb:YAG disk modules are placed at a symmetrical position inside the resonator to increase stability and efficiency of the laser. The output of the proposed laser with two Yb:YAG disk modules has a slope efficiency of 11.6 % and a beam quality () of 1.05∼1.18. We find that the output power of the laser with two Yb: YAG disk laser modules is approximately two times of the output power of the laser with single Yb: YAG disk. We additionally perform Q-switching pulse generation by coupling SESAM to the designed laser with two Yb:YAG disk laser modules. The Q-switched output has an average power of 1.76 W at a 36 kHz repetition rate and the pulse width of about 960 ns when the power of a pumping laser diode is 14.6 W.