Shock waves in GaSe semiconductors were produced by high-power picosecond laser pulses. Spontaneous and stimulated emissions in GaSe were used to probe the effect of shock waves. Under the laser-driven shock loading, a 24-nm spectral red-shift of the spontaneous-emission peak position, which corresponds to 14-kbar shock pressure, was detected. Significant line broadening of the spontaneous emission is attributed to the shock-wave-induced collision mechanism. The observed larger red-shift of 36 nm and the intensity decrease of the stimulated-emission peak were explained by the shock-wave-induced band-gap shrinkage through the gain-reduction mechanism based on the exciton-exciton scattering process in GaSe.

• Received 30 October 1986

DOI:https://doi.org/10.1103/PhysRevB.35.7515