Abstract

Almost all current results on ultrafast processes are derived from femtosecond lasers in the visible or near infrared. There is a clear need to extend the wavelength range of high repetition rate femtosecond pulses into the ultraviolet (uv). Frequency doubling (SHG), both extra¹- and intracavity², represents one technique for generating such pulses. However, the results achieved so far have been far short of what have been achieved in the visible. In this talk, we report an intracavity doubling experiment using the new nonlinear optical crystal β-BaB₂O₄ (BBO) that results in nearly complete recovery of the normal visible fundamental output power in the form of femtosecond uv pulses at the second harmonic. Recent success in our laboratory in growing and fabricating high quality BBO crystals³ has enabled us to generate the shortest uv pulses reported so far, less than 45 fs at 315 nm.

© 1988 Optical Society of America