Abstract

The fluorescence spectra of Czochralksi grown titanium doped sapphire crystals have been investigated for temperatures ranging from 13K to 578K. Selected spectra are shown in Figure 1. An emission band peaked at about 13,300cm⁻¹ is observed at temperatures above 125K to be broad and structureless except for persistent lines tentatively identified as due to chromium impurities. Zero- and multi-phonon assisted electronic transitions are observed at temperatures below 125K on the high energy side of the fluorescence spectra. Three lines (two narrow and strong, and one broad and weak) near 16,200cm⁻¹ are attributed to zero phonon transitions from the upper ²E_g level to the E_3/2, ₁E_1/2 and ₂E_l/2 levels. The energy difference between these peaks agree with experimental and theoretical values published in the literature.(1-5) Analysis of the line structure on the low energy side of the zero phonon lines suggest two modes of lattice vibration couple to the electronic ²T_2g state with energies of 220cm⁻¹ and 260cm⁻¹.

© 1985 Optical Society of America