Only the thinnest optical device with three atoms is available
According to the latest issue of "Natural Nanotechnology", American scientists have developed the world's thinnest optical device-a waveguide that is only 3 atoms thick. The research results can reduce the size of existing optical devices by several orders of magnitude, or bring higher density and higher capacity photonic chips. The new waveguide, developed by the University of California, San Diego, is about 6 Angstroms thick (1 Angstrom = 10-10 meters), which is 10,000 times thinner than typical optical fibers and about 500 times thinner than on-chip optical waveguides in integrated photonic circuits. The waveguide consists of a single layer of tungsten disulfide (two layers of sulfur atoms sandwiched by a layer of tungsten atoms) suspended on a silicon frame. The single layer consists of a series of nanopore patterns to form a photonic crystal. The special feature of this single-layer crystal is that it can support electron-hole pairs called excitons at room temperature. These excitons produce a strong optical response, making the refractive index of the crystal about 4 times the refractive index of the air surrounding its surface. In contrast, another material with the same thickness does not have such a high refractive index. When light travels through the crystal, it is captured internally and conducted along the plane through total internal reflection. Another feature of this waveguide is that it can conduct light in the visible spectrum. Nanopores etched into the crystal allow some light to be scattered perpendicular to the plane, allowing observation and detection. The periodic structure produced by this array of holes allows the crystal to function as a resonator. The system can not only resonantly enhance the interaction of light and matter, but also act as a second-order grating coupler to couple light into the optical waveguide. Flange Ball Valve,Flanged Float Valve,Flanged Ball Check Valve,Stainless Steel Flanged Ball Valves Wenzhou Dico Valve Technology Co.,Ltd. , https://www.dicovalves.com
