Spectro-temporal characterization of a femtosecond white-light continuum by transient-grating diffraction

An optically induced transient grating in a wide-bandgap dielectric is used to characterize the dispersion of a femtosecond white-light continuum over a 700 nm spectral range and with a time resolution of approximately 20 fs. With this technique, the dependence of the continuum dispersion on the foc using into the nonlinear material is investigated. Implications for laser s pectroscopy experiments with continuum pulses are discussed. (C) 2000 Elsev ier Science B.V. All rights reserved.