Optical absorption of octahedral ions Fe2+, Fe4+ and photoinduced effect in YIG single crystals

The peculiarities of optical absorption of octahedral ions Fe2+ and Fe4+ have been analyzed at various parameters of a trigonal and non-trigonal field by taking into account the transitions between levels of a split ground state. The spectral dependence of optical absorption coefficient on parameters of a crystal field has been constructed. The differences of optical absorption spectra that arise with redistribution and change of quantity of ions Fe2+ and Fe4+ have been considered. The explanation of experimental results on photoinduced changes of optical absorption in yttrium ferrite garnet single crystals has been proposed. (C) 2003 Elsevier B.V. All rights reserved.