Site selective spectroscopy and fluorescence line narrowing of trivalent chromium impurities in Na3Li3In2F12 garnet

Abstract We present the results of a spectroscopic investigation on a Cr-doped fluoride garnet. The emission is consistent with that of Cr 3+ in a slightly distorted octahedral crystalline field. Several emitting centres are present, fluorescence line narrowing (FLN), and site selective emission spectra show that all the observed emissions arise from trivalent chromium in trigonal sites. The sign of the trigonal distortion and the role of the Jahn-Teller effect are discussed on the basis of site selective excitation spectra.