Abstract

When a femtosecond white-light continuum pulse is used in femtosecond spectroscopy, the frequency chirp due to groupvelocity dispersion in optical elements must be eliminated to avoid a wavelength-dependent time-delay distortion. Since groupvelocity dispersion is difficult to eliminate over the whole spectral range of the continuum, a delay-time correction in the transient spectra is often performed. The objective of this paper is to show that there is a residual effect of the chirp that cannot be removed even after delay-time correction. To demonstrate this effect we measured the phase and amplitude change of the chirped continuum due to the optical Kerr response in CS₂ with a frequency-domain interferometer, which we recently developed,¹ with white-light continuum pulses for the probe and reference and with fundamental pulses of 620 nm for the pump.

© 1993 Optical Society of America