[OPTICAL REVIEW Vol. 7, No. 6 (2000) 511-519]

Passive Q-switches for Nd:hosted Solid State Lasers

Junewen CHEN,1,2 Hong-Chang KUNG,1 Hon-Fai YAU,2 Hai-Pei LIU,2 Tzu-Chiang CHEN2 and Chao-Chia CHENG2

1Chung-Shan Institute of Science and Technology, P. O. Box 90008-8-10, Lung-Tan, Taiwan 325, R.O.C., 2Institute of Optical Sciences, National Central University, Chung-Li, Taiwan, R.O.C.

(Received March 3, 2000; Accepted July 20, 2000)

The currently available Nd:hosted lasers utilizing passive Q-switches: a plastic dye sheet, a LiF:F2 color center crystal, a Cr4+:YAG crystal or a RG1000 colored glass filter have been investigated in detail and the results summarized for comparison purposes for the first time. We first briefly summarize our own and others' past studies, and report on recent new results concerning the use of Cr4+:YAG crystals and RG1000 colored glass filters as Nd:hosted laser passive Q-switchings. We then investigate in detail solid state laser system design using the above four passive modulators. Typical interpretations are given based on characteristic features of the materials, such as their saturation intensity and relaxation times. The results are then explained via adequate equations derived with respect to the relevant physical parameters of the materials. The optical density selection of plastic dye sheet passive Q-switching for the Nd:YAG laser system design is verified quantitatively, and the slope effciencies from plastic dye sheet passive Q-switched operation by single pulse and multiple pulse bursts are investigated. The multi-peak Q-switched pulse timing phenomena are presented as well. The outstanding annealability, long lifetime, inexpensiveness and high repetition rate operation of LiF:F2 crystals are highly recommended.

Key words : Q-switching, Nd:YAG laser, Nd:glass laser, Nd: YVO4 laser, plastic dye sheet, LiF: F2 color center crystal, Cr4+:YAG crystal, RG1000 colored glass filter