Abstract

Much effort has been put in the development of schemes for further pulse compression of femtosecond laser systems. For instance, the combination of an amplified 20-fs Ti:sapphire kHz-laser system with a gas-filled hollow fiber for frequency broadening and a set of chirped mirrors and a prism set for compression has led to sub-5 fs pulses, the shortest energetic pulses reported to date around 800 nm [1]. For spectroscopic purposes extremely short pulses at high repetition rates are desirable in the vsisible, U V or even VUV. Frequency conversion techniques are then to be used in conjunction with compression schemes. Recently we have shown that 20 fs pulses can be generated in the region between 360-440 nm [2]. The limiting factor for further pulse shortening has been due to spectral cubic phase introduced by the compressor stage.

© 1998 IEEE