Stimulated Infrared Emission from Sm Centers in SrS Phosphors

Abstract

Previous investigations of the two phosphor system SrS: Ce, Sm and SrS: Eu, Sm indicated that two energy levels within the energy gap were associated with the Sm site. Under certain conditions one expected that a transition between these two levels of the same center would result in an infrared emission. This emission was not seen at room temperature but it has recently been observed at 77°K under dynamic conditions of simultaneous irradiation by ultraviolet and visible light. Correlation is made between the observed emission and the simplified band-theory model proposed earlier.