ON THE QUANTUM EFFICIENCY OF CHROMIUM-DOPED GLASSES

It is argued that in chromium-doped glasses the environment about the chromium ion can undergo a much greater deformation, when the electronic state of the ion changes from 4A2 to 4T2, than is the case for most crystalline materials. An increased deformation enhances the probability for multiphonon relaxation. The case of Cr3+ ions in low field sites in oxide glasses is considered. The large deformation shows up as a large Stokes shift of the 4T2 ↔ 4A2 transitions, and it is argued that the enhanced multiphonon relaxation is responsible for the low quantum efficiency of broadband-emitting chromium-doped glasses. © 1990.