Conversion of optical signals in a laser with an intracavity liquid-crystal spatial modulator

Abstract

The thermoreflectance of YIG single crystals was measured in the visible energy range. Spectra of this compound support a model that incorporates both localised and oneelectron band states. All structures of the thermoreflectance spectra exhibit temperature dependence. Those at low energies, which occur at 16390, 17220, 19321, 20350, 21450, 22410, 23609 and 24271 cm-' and exhibit a small temperature shift and broadening, were assigned to crystal-field-split localised interionic transitions between the 3d states of Fe3+. The other structures, occurring at 25775, 27367, 30453, 32500, 35248, 39514 and 44202 cm-' with a considerable temperature shift (between 2 x loT3 and 8 x 10-4eVK-') and broadening were ascribed to pair transitions between the 3d states of iron and/or to charge-transfer transitions involving delocalised valence-band oxygen states and iron d-like bands.