Frequency-domain nanosecond population-grating spectroscopy in semiconductor doped glass

We have observed coherent emission from nanosecond laser-induced population -grating in fundamental absorption edge of semiconductor doped glass at bot h 10 and 300 K. The third-order nonlinear response was influenced definitel y by the confined exciton energy relaxation. The results on the excitation frequency dependence suggest that a low-frequency acoustic mode mediated by the laser-induced thermal grating contributes dominantly to the exciton en ergy relaxation. (C) 2000 Elsevier Science B.V. All rights reserved.