A detailed experimental study of the holographic gratings recorded in nonannealed amorphous As<sub>2</sub>S<sub>3</sub> films by 514.5-nm light in the presence of 632.8-nm readout light is carried out. A strong influence of a continuous 632.8-nm readout is found. The dependences of the maximal first-order diffraction efficiency and the corresponding specific recording energy on the holographic grating period were studied in a wide range of periods from 0.40 to 70.0 µm for 2-yr-old films. The obtained results are discussed in terms of photoinduced structural changes, relaxational structural changes, photoinduced anisotropy, and photoinduced recharging of the localized states in the bandgap. The photoinduced sulphur related D<sup>−</sup>- and D<sup>+</sup>-center orientation mechanism is proposed to explain the stimulating action of 632.8-nm light.
© 1998 Optical Society of America
(050.2770) Diffraction and gratings : Gratings
(160.2750) Materials : Glass and other amorphous materials
(160.2900) Materials : Optical storage materials
(310.6860) Thin films : Thin films, optical properties
A. Ozols, O. Nordman, and N. Nordman, "Two-color holographic-grating formation in amorphous As2S3 films," J. Opt. Soc. Am. B 15, 2355-2360 (1998)