Optical properties of chalcogenide multilayer deposited on Au layer

Abstract

The chalcogenide multilayers were prepared as dielectric mirrors having the first order stop bands in the near infrared region ∼1.55 μm. The 7.5 layer pairs of the alternating amorphous Sb–Se and As–S layers were deposited on glass substrates using a conventional thermal evaporation method. To center the stop bands of the 15-layer dielectric mirrors at 1.55 μm, the layer thicknesses 117 nm for Sb–Se and 169 nm for As–S single layers were calculated from the quarter wave stack condition. The optical reflection and transmission spectra of the prepared mirrors were measured using a UV/VIS/NIR and FT-IR spectroscopy at the ambient and elevated temperatures. The optical reflection of the annealed 15-layer chalcogenide mirror was found higher than 99% in the range of 1440–1600 nm. As the 200 nm thick gold layer was added between the substrate and the chalcogenide mirror, the stop band of the annealed Au/multilayer system broadened to 1360–1740 nm simultaneously with an appearance of the ∼15% transmission peak at 1.55 μm. A preparation of similar metal/multilayer systems is one of the possible ways how to design the dielectric filters for near infrared region exploiting the good optical quality of the chalcogenide films and their simple deposition.