Ursula Keller (AT&T Bell Laboratories, Holmdel, N.J.): "Until the late 1980s, advances in ultrashort pulse generation were dominated by dye lasers. These ultrafast laser systems with pulse duration shorter than 100 femtoseconds are relatively large, are maintenance-intensive, and require a laboratory environment with a skilled technician or scientist to operate. An all-solid-state laser technology could provide a compact, reliable, push-button type of a laser. The development of diode-pumped solid-state lasers addressed these issues; however, for ultrashort solid- state lasers, a broad gain bandwidth was required.
"Renewed research efforts in tunable solid-state lasers produced the first demonstration of the Ti:sapphire laser and, more recently, diode-pumped laser materials such as Cr:LiSAF. The development of such laser materials was crucial in the current rapid developments in femto-second pulse generation.
"One key issue for solid-state lasers is the mode-locking mechanism, which produces ultrashort pulses. Because diode-pumped solid-state lasers typically have about a 1,000 times ...
