Photoinduced anisotropy (PA) in films and bulk samples of chalcogenide glasses As2S3, As50Se50 and Ge20As20S60 has been studied in a wide spectral range (1.5 to 5.5 eV) using reflectance difference spectroscopy (RDS). PA was observed in the energy range much exceeding the energy of inducing photons and also in the range 4.5-5.5 eV energies greater than band gap energy for our samples. The sign of reflectance anisotropy induced by the near-band-gap light was shown to be opposite at smaller and larger energies. The conclusion is made that not only defects and scattering centers but also interatomic covalent bonds can be oriented and reoriented with linearly polarized light. A model of redistribution between bonding and lone-pair electrons is proposed.
- Polarized light