Light-induced optical absorption in the garnet Ca3Mn2Ge3O12

Abstract

Light-induced change in the optical absorption of the garnet Ca3Mn2Ge3O12 has been found. The magnitude of the light-induced optical absorption does not depend on the polarization state of the exciting illumination. The effect persists for a long time at low temperatures and can be attributed to light-induced generation or redistribution of Mn4+ ions in the crystal.

Photoproduction of long-lived holes and electronic processes in intrinsic electric fields seen through photoinduced absorption and dichroism in Ca3Ga2 xMnxGe3O12garnets

“…As was shown earlier by the authors [13], dichroism and birefringence [27,28], induced by linearly polarized light in the Ca 3 Mn 2 Ge 3 O 12 garnet, are of the same nature, judging from the coincidence of their temperature dependences under pumping and relaxation kinetics after switching off irradiation. Most probably, the mechanism of both phenomena involves twosite hole polarons in the O 2− sublattice.…”

Specific Recording Kinetics as a General Property of Unconventional Photorefractive Media

“…This class comprises media with completely different origins of the photorefractive response such as, e.g., photorefractive garnets [8,[13][14][15], nitroprussides [9,16], or crystals with DX center defects [10,17,18]. Although the recording of holograms has been investigated intensively in these media a convincing description of the respective kinetics is still missing and cannot be explained by the wellknown models.…”

Photoinduced optical absorption in Ca3Ga2Ge3O12:Mn garnet

“…[1][2][3][4][5][6] Illumination of such crystals with linearly polarized light can induce a change of magnetic anisotropy, linear dichroism, domain structure, and linear birefringence. Irradiation with unpolarized light causes a change of magnetic susceptibility, coercivity, and mobility of domain walls, magnetostriction, and optical absorption.…”

“…[1][2][3][4][5][6] Recently, the authors developed the model of active charges ͑hole polarons͒, 7,8 describing the mechanism of photoinduced optical absorption in Ca 3 Mn 2 Ge 3 O 12 . Under illumination, holes are transferred from the Mn 4ϩ ions, coupled with negative impurity ions or cation vacancies, to regular Mn 3ϩ ions, thus creating spatially separated charges of opposite signs ͑active charges͒.…”