Optical spectra of Vte LiNbO3: Cr

Abstract The luminescence in the region 13 350–13 900 cm−1 of 2E → 4A2 transitions of Cr3+ are studied at 5, 50 and 80K with congruent and stoichiometric LiNbO3: Cr (0.1 mol%) specimens are obtained using the Vapour Transport Equilibrium (VTE) procedure. Twelve emission lines were observed in stoichiometric crystals and 7 in congruent ones. Emission lines in VTE specimens vs. congruent ones shift a little to lower energies and linewidth decreases by about factor 2.5. The emission lines peaking at 13 420 and 13 540 cm−1 seem to be depressed in congruent specimens and the emission line at 13 613 cm−1 seems to be very weak in stiochiometric ones. In region 5–80 K luminescence intensity decreases with temperature in congruent specimens, but increases VTE ones. A possible origin of the emission lines observed is discussed.