Abstract

Kerr lens mode-locking (KLM) has been increasingly acknowledged as a reliable method of producing femtosecond pulses from Ti:sapphire and Cr:LiSAF laser systems.^1,2 However, the previous thresholds for KLM action have been relatively high, and the production of femtosecond pulses has required large frame Ar+ or Kr+ pump lasers. To realise an all solidstate femtosecond system Cr:LiSAF has been extensively studied, since it has a significantly lower laser threshold and requires a red pump source compatible with the high power red diodes. However, the low brightness of red diodes prevents accurate mode matching of the pump beam to the Cr:LiSAF KLM laser mode, thus raising the Cr:LiSAF threshold and, to date, preventing operation of a directly diode pumped KLM Cr:LiSAF system.³

© 1994 IEEE