High nonlinear behavior of optical reflectivity in surface plasmon resonance structures which contain amorphous As_2S_3 thin films

摘要

The amorphous films show many physical properties which differ from the crystalline state. One of these is the optical transparency photoinduced by light with photon energies higher than optical bandgap. The phenomenon is especially large in amorphous chalcogenide films. However, the changes of optical constants are too small for optoelectronic applications. In this paper we consider structure were the amorphous As_2S_3 film is placed in a structure which forms a surface plasmon resonance structure. The reflected light is coupled with waveguide modes. The experimental studies show that high nonlinear changes may be achieved for the light intensity of 10- 12 mW when the incident angle is close to resonance. For some film thicknesses the SPR resonance was achieved with prism made from BK7 glass, which is important opportunity for applications.