Compression and Shaping of Femtosecond Pulses

Abstract

During the Past several years ultrashort pulse technology has advanced dramatically from the picosecond to the femtosecond time domain. The colliding-pulse modelocked (CPM) cw dye laser [1] is now a reliable source of pulses shorter than 100 fsec; and pulses from other laser systems are being compressed to similar durations by nonlinear optical fiber methods [2]. Fiber compression of amplified pulses from a CPM-based system has already been used to generate 30 fsec pulses [3]. In the first part of this paper we describe experiments in which this same combination of techniques has been extended to produce pulses as short as 16 fsec [4]. These pulses, with a center wavelength of about 625 nm, are comprised of only 8 optical cycles. Then, as an application for such ultrashort pulses, we describe tine-resolved reflectometry studies of multilayer dielectric mirror coatings. Dramatic pulse distortions can be observed after a single reflection from a broadband mirror. Finally, we discuss the use of transient four-wave mixing for pulse shortening and sharing at much higher power levels.