Abstract
Characteristics of a simple but practical ultrashort pulse laser system for transient nonlinear spectroscopy around and below 100 fs are described. The system is based on a hybridly mode-locked, cavitydumped cw dye laser, with high stability, broad tunability and specific phase properties, producing both clean transform-limited and chirped pulses. The laser system is applied to demonstrate the feasibility of using chirped pulses in high time-resolution measurement of relaxation times in condensed matter by means of degenerate transient four-wave mixing