Stimulated luminescence from chromate ions adsorbed on disperse silica surfaces under intense ultraviolet excitation

Yuri D. Glinka
1997 Applied Physics Letters  
Luminescence measurements of chromate ions (CrO 4 2Ϫ ) adsorbed onto disperse silica (SiO 2 ) surfaces under intense pulsed ultraviolet excitation ͑ exc ϭ354.7 or 266 nm, p ϭ20 ns͒ were performed at room temperature. The luminescence spectra were collected for different values of the excitation intensity ͑I͒. The luminescence yield in the red band corresponding to emission from CrO 4 2Ϫ ions varies linearly with I under 354.7 nm excitation. However, the intensity dependence of the luminescence
more » ... f the luminescence yield under 266 nm excitation is characterized by a threshold (Iϳ0.6 ϫ10 6 W cm Ϫ2 ), after which the intensity dependence of the luminescence yield is described by a power law with index nϭ1.7 and then saturated at Iϳ1.0ϫ10 6 W cm Ϫ2 . This feature of the excitation dynamics has been attributed to stimulated emission and considered by means of a four-level scheme. The cross section of stimulated emission was estimated as ϳ3.3ϫ10 Ϫ21 cm 2 .
doi:10.1063/1.119796 fatcat:fqvvdmeps5dobknnfgptllfify