Abstract

By employing amplitude sensitive picosecond excite-probe techniques we have recently shown how remarkable detail can be obtained about the energetics and evolution of dilute excitonic systems in a number of compound semiconductors and mixed crystals (1,2). The experiments, which utilize high data rate averaging, are based on a pair of synchronously pumped dye lasers in an arrangement where transient photomodulated spectra (in transmission or reflection) are typically examined from approximately 1 to 1000 psec following excitation. The relatively high spectral resolution (about .3 meV) makes the detailed study of transient exciton phenomena attractive, coupled with an ability to measure very small excitation induced fractional changes in the optical constants of an exciton resonance. Thus we specifically attempt to avoid both the free exciton Mott transition and saturation of bound exciton states.

© 1984 Optical Society of America