Amorphous arsenic selenide films for optical memory based on surface plasmon resonance

We present a theoretical study on the reflectivity of a plasmonic structure based on As2Se3 amorphous chalcogenide film as a function of the refractive index of the chalcogenide film. In plasmonic configuration, the thin chalcogenide films constitute an optical waveguide, and we show that for specific thicknesses of the plasmonic structure layers, the reading-laser radiation can excite TM waveguide modes efficiently. Thus, we demonstrate that for chalcogenide film thickness of 700 nm, the resonance coupling-angle is equal to 49.16 degrees at the reading-laser wavelength of 1064 nm. When irradiating the chalcogenide film with a linearly polarized writing-laser at a wavelength in the absorption edge of the chalcogenide, the resonance peak experiences a large shift due to the laser induced variation of the chalcogenide refractive index. This enabled us to demonstrate that by keeping a constant incidence angle of 50.0 degrees, which is slightly above the resonance angle, a sharp peak of the reflectivity at the reading-laser wavelength is observed when increasing the chalcogenide refractive index with similar to 0.5% by writing-laser irradiation. The results presented here can be used for development of devices with bistability or optical memory.