Miniaturizing Photonic Devices to Integrate Into Computer Chips

The smallest photonic devices are limited to sizes of at least a micrometer. Researchers from Singapore's A*STAR Institute of Microelectronics have demonstrated a device design that beats such size restrictions and can be easily integrated into a silicon chip. The researchers say that by using plasmonic techniques, they demonstrated optical resonator structures, which allow a beam of light to circulate in a closed path and can be used as on-off switches for light. These plasmonic resonator devices were built from two copper structures - a long wire next to a circle - that guide light along them. The smallest width of the copper circuit is around 180 nanometers - much smaller than conventional light guides. The proximity of the wire and the circle is critical for efficient device operation. When light of a specific wavelength, which is determined by the dimensions of the circle, passes through the wire, some of it can leak into the circle where it becomes trapped. Light can only pass through the structure if it does not match the resonance wavelength of the circle.