Photonics: First All-Optical Nanowire Switch

Researchers at the University of Pennsylvania have made an important advance in this frontier of photonics, fashioning the first all-optical photonic switch out of cadmium sulfide nanowires. Moreover, they combined these photonic switches into a logic gate, a fundamental component of computer chips that process information. The research team's innovation built upon their earlier research, which showed that their cadmium sulfide nanowires exhibited extremely strong light-matter coupling, making them especially efficient at manipulating light. This quality is crucial for the development of nanoscale photonic circuits, as existing mechanisms for controlling the flow of light are bulkier and require more energy than their electronic analogs. "Once we have the light in the second segment, we shine another light through the structure and turn off what is being transported through that wire," Agarwal said. "That's what makes it a switch." "Putting switches together lets you make logic gates, and assembling logic gates allows you to do computation," Piccione said. "We used these optical switches to construct a NAND gate, which is a fundamental building block of modern computer processing."