Enhanced photoinduced circular and linear dichroism in Si doped yttrium iron garnet

Abstract

Magnetic circular and linear dichroism are photoinduced by means of linearly polarized light in a single crystal YIG(Si) containing 0.04 Si 4+ per formula, utilizing both the conventional and an “enhancing” scheme that greatly increases the magnitude of the photoinduced effects. The measurements are made at 4.2 K and at λ = 1.2 μm. The enhanced effects are found to be about six times larger than the ones obtained conventionally. Furthermore, the technique of magnetic circular dichroism (MCD) recently proposed by Tucciarone is applied to obtain additional information on the Fe 2+ active centers: MCD was measured at 4.2 K and for λ = 1.1−1.6 μm. In particular, the MCD measurements are shown to provide a direct determination of the Fe 2+ ions photoinduced shift: δN/ N = 1.8% in the case of the “enhancing” procedure.