Optical spectra and relaxation of Cr3+ ions in YAlO3

Abstract

Optical absorption and emission spectra of Cr3+ ions in YAlO3 have been investigated at 300 and 77°K. In the cubic field approximation, the spectra can be fitted by the parameters Dq = 1800 cm−1, B = 590 cm−1, C = 2980 cm−1. An intense vibronic spectrum is associated with 2E → 4A2 fluorescence transitions. Measurements of absorption cross sections and oscillator strengths, thermal broadening and shifts of the R-line fluorescence, and lifetimes of the 2E fluorescence and Cr3+-Cr3+ pair lines are reported. At low temperatures and chromium concentrations, the radiative quantum efficiency of the 2E state is approximately unity. Other relaxation processes become important at temperatures > 400°K. The possibility of observing stimulated emission from YAlO3:Cr3+ is discussed.

Cr+3 Distribution in Al1 and Al2 Sites of Alexandrite (BeAl2O4: Cr3+) Induced by Annealing, Investigated by Optical Spectroscopy

“…Previous published data [13] show that spectroscopic properties of Cr 3+ ion in alexandrite are similar to 3 . In all of them, the spectra present two well defined lines 4 A 2g  2 E g (R lines) and two wide absorption bands.…”

Research on the thermal shifts and electron–phonon coupling parameters of Ri lines for Cr3+ ions in LaGaO3 and LaAlO3 crystals

“…These values are smaller than those in the range 400-720 cm À 1 [28] for Cr 3 þ in the garnet-type crystals. Considering that (i) the crystal field parameters 10 Dq (Z18000 cm À 1 , corresponding to 4 T 2 -4 A 2 transition) for Cr 3 þ in the perovskite-type crystals [15,20,34] are larger than those ( r17000 cm À 1 ) for Cr 3 þ in the garnet-type crystals [35] and (ii) the smaller energy difference between the first excited state 2 E (i.e. R-line position) and the 4 T 2 state can result in the stronger admixture and hence the stronger electron-phonon coupling [28,33], the smaller true electronphonon coupling parameters αʹ for Cr 3 þ ions in the perovskitetype crystals can be understood.…”

Crystal growth and luminescence properties of Cr-doped YAlO3 single crystals

“…It is due to the large ionic radius of Cr 3 þ (coordination 6, 0.615Å) compared to Al 3 þ (coordination 6, 0.535Å) [12]. [9]. The absorption became larger with the increase of Cr concentration.…”

“…The absorption became larger with the increase of Cr concentration. Absorption bands in 200-300 nm are due to the host lattice [9].…”

“…Laser materials activated with Cr 3 þ are well known like Cr-doped LiCaAlF 6 , LiSrAlF 6 and BeAl 2 O 4 [5][6][7][8]. Although optical spectra of Cr-doped YAP (Cr:YAP) have been reported, to our knowledge, scintillation properties of Cr:YAP under X-ray excitation have not been studied so far [9].…”