https://doi.org/10.15407/jopt.2018.53.240

Optoelectron. Semicond. Tech. 53, 240-247 (2018)

A. Meshalkin1, A.P. Paiuk2, L.A. Revutska3, E. Achimova1, A.V. Stronski2, A. Prisakar1, G. Triduh1, V. Abashkin1, A. Korchevoy2, V.Yu. Goroneskul2

DIRECT SURFACE-RELIEF GRATING RECORDING USING SELENIUM LAYERS

This paper presents the spectral dependences of the transmittance in the 500…900 nm range for selenium layers (with their thickness 630 and 1030 nm) that were prepared using the method of thermal vacuum deposition. The optical constants of the Se layers were obtained from the transmission spectra: the absorption coefficient for the Se layer is 9·104 cm–1 for the recording wavelength of 532 nm. Using the spectral dependence of the absorption coefficient in quadratic coordinates (the Tauc method), the optical band gap Eg opt was determined as 1.92 eV. The parameters of the single-oscillator model for the Se layers have been given. The Raman spectra of the Se films have been presented. There is a main peak at 251 cm–1, which is associated with stretching vibrations in the Se8 fragments as well as in chain fragments, and weaker bands at 80 and 109 cm–1. From the differential Raman spectra presented in this paper, it can be seen that the structure of the Se films changes upon interaction with light. With increasing the exposure, the intensity of 235 cm–1 band increases, and the intensity of 251cm–1 band decreases, which is also characteristic to 80 and 109 cm-1 bands. The shoulder that appears at 235 cm–1 may be caused by the presence of a small fraction of “pure” helicoid chains. To record holographic diffraction gratings with a period of 1 μm, the radiation of a DPSS laser with the wavelength 532 nm and a Se film were used for data recording. Simultaneously with recording the diffraction gratings, the diffraction efficiency of the gratings was measured in the first diffraction order for transmission by using radiation 247 from a laser diode with the wavelength of 650 nm. Gratings with the diffraction efficiency close to 22% were obtained. The profile of the relief was similar to the sinusoidal one. It has been shown that a pulse-like recording makes it possible to obtain diffraction gratings with sufficiently high transmission efficiency (22%) using Se layers as recording media. The obtained depth of the grating relief was approximately 140 nm. A good agreement was obtained for the experimentally obtained diffraction efficiency of the gratings in transmission and the theoretical ones (the discrepancy is ~ 6%).

Keywords: hologram diffraction grating, chalcogenide glass, multilayer nanostructure, optical properties, Raman spectrum, AFM.