Optical Control of Light on a Silicon Chip

An anonymous reader writes "Researchers at Cornell University have demonstrated a device that allows one low-powered beam of light to switch another on and off, on silicon, a key component for future "photonic" microcircuits in which light replaces electrons for propagating signals. It is highly desirable to use silicon--the dominant material in the microelectronic industry--as the platform for these photonic chips. The approach developed confines the beam to be switched in a circular resonator, greatly reducing the footprint required on the chip and allowing a very small change in refractive index to shift the material from transparent to opaque."