Abstract

A principal problem in obtaining optical pulses with bandwidths approximating that of the visible spectrum and durations approaching the transform limit has been the uncompensated cubic phase distortion of pulses compressed by grating pairs. We describe the use of combined prism and grating sequences to compensate not only the quadratic, but also the cubic, phase distortion of optical pulses frequency broadened in an optical fiber. We obtain pulses of 6-fs duration which can be used on a routine basis for time-resolved spectroscopy. We have used these pulses to study the dynamics of spectral hole burning in organic dye molecules and in semiconductor materials. Examples are given of recent work on molecules, such as cresyl violet and Nile blue, and on semi-conductor materials, such as GaAs. We have also used these 6-fs pulses to examine the optical Stark effect in organic dye molecules such as rhodamine B and rhodamine 6G. We obtain, in particular, direct observations of the dynamic shift of the rhodamine B absorption spectrum on a femtosecond time scale. We also use the intensity dependence of these shifts as an alternate means of measuring the molecular dipole moment.

© 1987 Optical Society of America