Abstract

Until recently the passively mode-locked dye laser has been the only reliable, widely used source of femtosecond optical pulses. The development of ultrafast all-optical amplitude modulation techniques that are capable of shaping optical pulses down to a few femtoseconds (additive-pulse mode locking, Kerr-lens mode locking) has opened the way for a new versatile femtosecond laser technology based on solid-state gain media. Almost three decades after the first demonstration of a picosecond mode-locked laser, we have recently witnessed the emergence and evolution of a new generation of ultrashort-pulse lasers based exclusively on solid state components.¹ Intensive research efforts resulted in a good understanding of the basic physical processes dominating pulse formation in these novel sources, giving rise to a rapid progress of femtosecond solid state laser technology. The evolution of ultrafast lasers recently culminated in the development of quartz-prism-controlled, selfmode-locked Ti:sapphire laser oscillators generating pulses around 10fs.^3,4

© 1995 IEEE