Abstract

Dye laser technology allows the direct generation of optical pulses of femtosecond duration at high repetition rates (74–200 MHz). At these high rates, sensitive differential techniques can be employed for small signal analysis; however, the relatively low pulse energies available limit the applicability of such systems. Amplification of femtosecond optical pulses makes possible a wide range of new investigations in nonlinear optics, spectroscopy, and high density phenomena; however, the repetition rate is then dictated by the pump source. Operation at intermediate repetition rates (1–10 kHz) provides a new and powerful combination: high peak powers (~50,000 times higher than direct laser output) and extensive signal averaging through the use of lock-in amplifiers, differential scanning optical multichannel analyzers, and point-by-point digital techniques. The techniques involved in the amplification and detection of femtosecond optical pulses in the kilohertz regime are discussed, as well as several illustrative applications.

© 1986 Optical Society of America