Photoluminescence due to exciton-exciton scattering in GaSe under picosecond laser excitations

Abstract

Picosecond-laser-excited photoluminescence spectra in GaSe at room temperature have been measured and analyzed.Both spontaneous and stimulated emissions were attributed to the excitonexciton scattering process in GaSe through a careful band-shape analysis. The exciton-photon coupling coefficient~a/@=3. 3)&10 ' was obtained from the spontaneous emission spectra fit. The stimulated emission is well explained by the optical gain mechanism arising from the reverse absorption process of the exciton-exciton scattering.

10.1007/s10789-008-4005-z

“…3a) can be understood in terms of exciton-exciton interactions, which cause excitons to fully disappear [10][11][12]. 3a) can be understood in terms of exciton-exciton interactions, which cause excitons to fully disappear [10][11][12].…”

“…Optical absorption, PC, and luminescence measurements indicate that GaSe crystals exhibit nonlinear light absorption due to exciton-exciton interactions [10][11][12]. The point is that the absorption edge of GaSe is due to excitonic transitions.…”

Untitled

“…The detection and investigation of thermal nonlinearity in GaSe crystals is of particular interest. Previously, optical nonlinearities of electronic origin were discovered in GaSe, such as harmonic generation [1,2], parametric light generation [3,4], electron-hole plasma [5][6][7][8][9], stimulated emission [10][11][12][13][14], multiphoton absorption [ 15,16], etc., have been observed in these crystals.…”

Thermal nonlinearities in GaSe

“…The detection and investigation of thermal nonlinearity in GaSe crystals is of particular interest. Previously, optical nonlinearities of electronic origin were discovered in GaSe, such as harmonic generation [1,2], parametric light generation [3,4], electron-hole plasma [5][6][7][8][9], stimulated emission [10][11][12][13][14], multiphoton absorption [ 15,16], etc., have been observed in these crystals.…”