Abstract

For the study of the ultrafast dynamics of elementary processes in physics, chemistry and biology femtosecond pulses in the visible and the UV are needed at spectral positions determined by the optical properties of the investigated system. Such pulses are not yet readily available at pulse lengths below 100 fs, despite the tunability of Ti: sapphire based systems in the near infrared. This is due to the fact that the group velocity mismatch (GVM) in nonlinear optical materials causes severe pulse lengthening in the nonlinear frequency conversion used for the generation of these pulses. We have used a multi-stage conversion scheme that by-passes these problems and is able to produce pulses of 50 fs length throughout the visible.

© 1996 Optical Society of America