Photoinduced Anisotropic Deformation in As₂S₃ Glass

Micron-scale deformations produced in a chalcogenide glass, As 2 S 3 , by illumination of focused linearly polarized light have been studied comparatively with optical and structural changes. In thin samples (∼2 µm), an anisotropic deformation, which is M-shaped along the electric field of light, grows after appearances of isotropic volume expansion and negative birefringence. In thick samples (∼10 µm), only the isotropic deformation appears. The anisotropic deformation is induced by subgap illumination more efficiently at 80 K. Raman-scattering spectra suggest that the anisotropic deformation accompanies stress at hillocks in the M-shaped deformation. These observations can be accounted for by assuming that the anisotropic deformation occurs through atomic layer alignment and fluidity, both being photoinduced.