De-Yuan SHEN,¹ Siu-Chung TAM¹, Yee-Loy LAM¹ and Takao KOBAYASHI²

¹Division of Microelectronics, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, ²Faculty of Engineering, Fukui University, 3-9-1 Bunkyo, Fukui, 910-8507 Japan

(Received May 2, 2000; Accepted May 22, 2000)

Laser-diode pumped passively Q-switched single-frequency Nd:YAG laser has been demonstrated with a Cr⁴⁺:YAG crystal as the saturable absorber. When pumped with a fiber-coupled CW laser diode, the laser produces pulses of 1.4-20.9 ns duration, with a repetition rate of 1.9-52.0 kHz. The highest peak power of 17.6 kW was obtained at an incident pump power of 1.8 W. The use of a Cr⁴⁺:YAG saturable absorber enables the laser to operate not only in a single-frequency mode but also linearly polarized. The mode selection mechanism is discussed.

Key words : Nd:YAG, Cr⁴⁺:YAG, Q-switch, single frequency

edyshen@ntu.edu.sg