Disorder and the optical spectroscopy of Cr³⁺-doped glasses: II. Glasses with high and low ligand fields

The paper reports spectroscopic studies of Cr³⁺ ions in fluorozirconate. fluoride, borate and telluride glasses in which the average strength of the octahedral crystal field Dq/B varies from 1.6 to 2.4. The emission spectra are shown to be inhomogeneously broadened by disorder. Non-exponential decay of the emission intensity following pulsed excitation is another signature of the extensive disorder in these glasses. The large density of states of two-level systems is shown to account for the larger-than-expected homogeneous width of the R line in lithium borate and potassium borate glasses.