Feature

New wavelength femtosecond dye lasers

Martin D. Dawson and Thomas F. Boggess

There is a continuing need for lasers capable of generating femtosecond optical pulses for application to investigations of ultrafast phenomena in chemistry, physics, biology, electronics, and communications. The most common source of these pulses is the passively mode-locked cw dye laser, which may be either continuously or synchronously pumped. From the inception of femtosecond spectroscopy in 1981 until very recently, such lasers operated almost exclusively using a single pair of dyes— Rhodamine 6G and DODCI—as the gain medium and the saturable absorber, respectively. This restricted direct femtosecond generation to the 600-635 nm spectral region.