Optical absorption spectrum of Cr^3+ in yttrium aluminum garnet

Abstract

Optical absorption measurements, made on yttrium aluminum garnet doped with 0.1% chromium, have been used to derive a crystal field potential expansion which predicts the locations of optical absorptions in this material. The locations of the 4FΓ5 and 4FΓ4, 4PΓ4 levels were determined to be 16700, 23200, and 35700 cm-1, respectively, by optical absorption measurements. From these results, the crystal field parameter Dq was found to be 1670 cm-1. The locations of the two Γ4 levels were fitted within 2.8% to the theory of Finkelstein and Van Vleck which predicts that the 4FΓ4 and 4PΓ4 states are coupled by the octahedral crystal field perturbation. The resulting crystal field expansion is Vj = -41400[ Y0 + (10/7)½(Y43 - Y4-3)].