Dot-matrix holographic recording in amorphous chalcogenide films

Abstract

We have developed PC controlled dot-matrix holographic recording system based on the CW diode pumped YAG:Nd SHG laser (wavelength 532 nm, power 30mW,) modulated electronically with TTL signals. Two-beam technique has been used with convergence angle 30o and PC controlled incident beam plane rotation 0-360o. Optical system consists of beam splitter, 40mm focus length forming cylindrical lens and 40mm focusing lens. Characteristic parameters of experimental equipment are following: spot size - 50-200 micrometers, direct laser writing area, limited by x-y positioning system, was 70mm x 70mm, number of writing head rotation positions up to 256 (8 bit), time of each exposure - 1-1000 msec. As the recording material we have used AsxSySe1-x chalcogenide glass material. Diffraction efficiency of written gratings in the material in dot-matrix regime exceeds 25%. Original method for surface relief enhancement by etching and subsequent electroplating has been developed. Special PC controlled device for thermal imprinting of relief holograms on the metallized polyamide film has been built. Measurements of light transmission, reflection, and diffraction phenomena of laser beams in processed chalcogenide materials are discussed.