A plasmonic cavity filled with active material is proposed to explain optical switching. Optical properties, including transmission, response time, and field distribution of on/off state, are numerically investigated. We demonstrate that such a gain-assisted plasmonic structure can achieve optical switching in the nanodomain and shorten the switching time to the subpicosecond level. Our results indicate the potential application of the proposed structure in optical communication and photonic integrated circuits.
The refractive index ofas-evaporatedamorphous semiconductor As2S8 film upon an annealing and saturation irradiation and annealing cycle is reversible. Upon successive treatment with annealing and non-saturation irradiation and further annealing, the refractive index of the as-evaporated amorphous semiconductor As2S8 film reaches a maximum value and then its reversibility occurs upon annealing. The annealing of the amorphous semiconductor AS2S8 films results in the stabilization of the structure through changes of the S-S bonds in the nearest environment, accompanied by a decrease of film thickness. The As2S8 planar waveguide after annealing （130 ℃） and saturation irradiation and annealing （130 ℃） shows a good propagation characteristic with ca, 0.27 dB/cm low propagation loss of the 632.8 nm guided mode.
