There exits the surface plasmon polaritons (SPPs) at a boundary between metal and the dielectric materials. SPPs provide the light energy localization and light field enhancement and their characteristics strongly depend on the structure size and shape of the metals. This features allows us to open new concept various device with nanotechnology, e.g., light energy harvesting devices with high quantum efficiency, tiny optical circuits beyond the diffraction limit of the light, and the artificial optical materials. Now, I am working on researches in metamaterials in the region from ultraviolet to infrared, plasmonic waveguide with the line width of submicron order for near infrared region, plasmonic functional devices built in the waveguide, devices plasmonic sensing devices, and so on.