Moving from the Picosecond to the Femtosecond Time Regime

Abstract

Considerable progress has taken place in the last decade and a half in the generation of ultrashort optical pulses. A steady progression of developments has led to ever shorter optical pulses and subsequent improvements in our ability to resolve fast spectroscopic events. In this discussion I will describe progress that has taken place in our laboratory which has led to the generation of optical pulses of less than 0.1 picoseconds in duration, pushing well into the femtosecond time regime. Three significant advances have taken place in the last two years which have made possible experimental investigations on a femtosecond time scale. The first key advance was the improvement of the passively modelocked dye laser [1] using the colliding pulse modelocked dye laser configuration [2]. With this laser the first pulses with a duration of less than 0.1 picoseconds were generated. The second important result is an improvement in amplification technique which has permitted the generation of femtosecond optical pulses of gigawatt intensities. The final point of discussion will be the use of pulse compression techniques to generate a 30 femtosecond optical pulse, the shortest optical pulse duration yet reported.