Photoinduced dichroism and the lack of a field effect

Abstract

The phenomenon of photoinduced dichroism in chalcogenide glasses requires a structural rearrangement of atoms in the localized region where the photon is absorbed. The structural change is facilitated by the energy released during electron‐hole recombination. The dichroism is induced because regions that preferentially absorb the incident polarization will be those that suffer the atomic rearrangements thus bleaching the material for that polarization. A strong electric field should break geminate pairs and transport the electron and hole away from the absorbing region which should quench the photoinduced dichroism. We have searched for such a field effect in glassy arsenic selenide at fields up to 10 V/μm. No decrease in the rate of induced dichroism is observed (the rate actually increases by about 10%) and no change is observed in the stretching parameter when the time dependence is fit to a stretched exponential. These results are consistent with those of other researchers who also failed to find a field effect. The implications of these results for the theory of photoinduced dichroism are discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)