Nanophotonics using optical near fields

This paper introduces recent successes in nanophotonics utilizing local electromagnetic interactions between a few nanometric elements (i.e., the optical near-field interaction). The sections of this paper review nanophotonic devices, nanofabrication, and systems for operating nanophotonic devices efficiently. Using CuCl quantum dots, the operations of an optical switch measuring 20-nm in size (i.e., a nanophotonic switch) and a nanometric optical condenser, which attracts optical energy into a 10-nm spot (i.e., an optical nano-fountain), were verified experimentally. The power consumption of these devices is only 1/100 000 that of conventional electronic devices. A nanodot coupler fabricated from a linear array of closely spaced metallic nanoparticles has also been introduced for transmitting an optical signal to a nanophotonic device. To increase the optical far- to near-field conversion efficiency for transmission, a surface plasmon polariton (SPP) condenser was fabricated from hemispherical metallic nanoparticles, so that it worked as a ‘phased array’. The SPP can be focused with a spot size as small as 400 nm.