Sten HELMFRID, Tetsuo ANDOU, Shinichi NAKATSUKA and Kimio TATSUNO

Central Research Laboratory, Hitachi Ltd., 1-280 Higashi-Koigakubo, Kokubunji, Tokyo, 185 Japan

(Received October 10, 1994; Accepted May 9, 1995)

When mini-solid-state lasers are end-pumped by diode lasers, it is important to have a good overlap between the pump beam and the oscillating mode and to have a pump spectrum that is narrow compared to the width of the absorption peak in the gain medium. We have theoretically studied the influence of the beam radius and the spectral width of the pump on the performance of diode-pumped devices. From the rate equations, the lasing threshold and the circulating intensity is evaluated numerically and the results can be used as a guideline in the design of intracavity doubling lasers. It is also shown that single-mode operation is more difficult when the pump spectrum becomes to wide.

Key words : diode-pumped, mini-solid-state-lasers, single-mode operation, pump spectrum