[OPTICAL REVIEW Vol. 8, No. 3 (2001) 163-168]
A Flash-Lamp-Pumped Nd:YAG Laser with Dual-Telescopic Optics Configuration
Hongru YANG1,2,*, Jingang LIU2, Deyuan SHEN2, Siu-Chung TAM2, Yee-Loy LAM2, Wenjie XIE2 and Takao KOBAYASHI1
1Department of Electrical and Electronic Engineering, Faculty of Engineering, Fukui University, 3-9-1, Bunkyo, Fukui, 910-8507 Japan 2School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798
(Received February 5, 2001; Accepted February 21, 2001)
A flash-lamp-pumped Nd:YAG laser that contains two laser rods and dual-telescopic elements is investigated theoretically and experimentally. The two intracavity telescopes of the resonator are appropriately chosen and adjusted to achieve a large-volume TEM00 mode inside the laser rods, and to minimize the variational effects of the thermal lens in the rods. The drift of the optimal operating point of the resonator caused by variation in the pump energy is compensated by adjusting defocusing of the two telescopes over a broad pump energy range. It is experimentally shown that our resonator geometry with appropriate parameters obtained the output energy of 560 mJ with 100 μs duration and slope efficiency of 3.5%, at a pump energy of 16 J, even though the misalignment tilting angle of the end mirror reached ±5 mrad. The bi-focusing effect caused by the thermally-induced stress birefringence was compensated by a 90° quartz rotator. Output energy was increased by 18% at the pump energy of 16 J. The misalignment tilting angle of the end mirror with intracavity telescope was 4 times larger than that without intracavity telescope.
Key words : solid-state laser, Nd:YAG laser, dual-telescopic, dynamically stable resonator, thermal lens and birefringence compensation