The low temperature photoluminescence from Cr3+ ions in Y3Al5O12 (YAG), Y3Ga5O12 (YGG), Gd3Sc2Ga3O12 (GSGG ) and Gd3Sc2Al3O12 (GSAG) have different characteristic lineshapes. YAG and YGG emit entirely in the R-lines with associated sidebands, whereas for GSGG and GSAG the emission is a mélange of R-line processes and broad 4T*2g→4A2g bands. This paper compares the experimental spectra of Cr3+ ions in these garnets in terms of the symmetry and energies of the vibrational models coupled to the electronic states. In GSGG, we have used fluorescence line narrowing (FLN) to probe the broadening of the vibronic structure introduced by compositional disorder.
- garnet crystals
- low temperature photoluminescence