High-order-dispersion control for the amplification and compression of femtosecond laser pulses.

Abstract

In this thesis many aspects of Chirped-Pulse Amplification (CPA) laser systems are addressed, including pulse duration, contrast, efficiency, compactness, and user-friendliness. A fundamental problem in ultrafast optics--namely, the compensation of high-order dispersion from an optical fiber--is solved, and we design a pulse compressor based on Carpenter prisms or 'grisms.' With this new compressor we demonstrate the first sub-picosecond CPA system with a fiber stretcher, whose compression factor of 750 is the largest obtained in a single-stage fiber-grating compressor. For ultrashort pulse production, an aberration-free stretcher-compressor system is designed to yield high-contrast, near-perfect compression of sub-50-fs pulses. We show that aberration-free stretchers and compressors utilizing identical gratings will be unable to support ultrashort pulses. However, the uncompensatable fourth-order dispersion of a matched-grating system can be eliminated by choosing compressor gratings with a different groove density than the stretcher gratings. Other system designs based on grisms, chirped gratings, and hybrid grating-prism combinations are shown to be useful in the production of short pulses in compact, efficient systems. Finally, we show that in the limit of strongly chirped pulses, nonlinear optical effects in the time domain are exactly equivalent to linear, stationary effects in the spectral domain. We propose a pulse-shaping system for CPA which will facilitate the production of ultrahigh-contrast pulses in the presence of nonlinearities.