Selectively excited luminescence and magnetic circular dichroism ofCr4+-doped YAG and YGG

Abstract

Site selective luminescence and magnetic circular dichroism experiments on Cr 4ϩ -doped yttrium aluminum garnet and yttrium gallium garnet have been made at low temperature. The spectral assignments for these near-IR lasing materials have been made using experimental data and ligand field calculations guided by the known geometry of the lattices. ͓S0163-1829͑99͒07003-4͔

Influence of Low-Symmetry Distortions on the Luminescence ofCr4+-Doped Forsterite

“…This redshift, coupled with the weak blueshift of the ͑ 3 T 2 ͒ 3 B 1 state, is responsible for the crossover. Recent results reported for isoelectronic Mn 51 [10,13] and angular overlap model calculations on Cr 41 :Y 3 Al 5 O 12 [8] also indicate that an increased distortion increases the splitting of the 1 E state and augments the redshift of its lowest orbital component ( 1 A 1 ). This effect further facilitates the ͑ 3 T 2 ͒ 3 B 1 -1 E electronic crossover.…”

“…Recent work on near-infrared (NIR) tunable solid state laser materials has focused on the dopant Cr 41 in several host lattices with Cr 41 :Mg 2 SiO 4 emerging as the leading technological system. The success of Cr 41 :Mg 2 SiO 4 as a tunable NIR laser material [1] has stimulated numerous recent studies of the spectroscopic properties of Cr 41 [2][3][4][5][6][7][8][9] and other 3d 2 dopants (Mn 51 , Fe 61 ) [10][11][12][13][14] because of the need for new NIR optical materials. Current work on Cr 41 :Mg 2 SiO 4 continues to focus on tunable NIR laser applications [15], as well as applications in frequency doubled visible [16] and ultrafast lasing [17].…”

Investigation on the valence of Cr ions in LiAlO2

“…The first excited state of the 3d 2 configuration is either 1 E or 3 T 2 , which are expected to lie above B6000 cm À1 as they do in Cr 4+ :forsterite [6,7] and Cr 4+ :garnets [8,9]. The EPR results suggest trivalent Cr ions with a 3d 3 configuration.…”

Crystal field analysis of energy level structure of LiAlO2:Cr4+ and LiGaO2:Cr4+

“…(1)- (4) , which are close to the value typical for the four-fold coordinated chromium ion [9,[13][14][15] , known as the nephelauxetic effect, is caused by covalency. This reduction for the Cr 4+ ion is larger than, for example, for the isoelectronic V 3+ ion, for which this parameter is β = 0.59 [14].…”