Rotating resonator creates a one-way street for light

Physics World  June 29, 2018
An international team of researchers (Israel, USA – University of Central Florida, University of Michigan, China, Japan) used a cylindrical, silica-glass resonator that is rotating on a turbine. An optical fibre is located 320 nm above the spinning resonator. Light travelling along the fibre interacting with the nearby resonator via the light’s short-range evanescent field perceives it to be less dense than light travelling in the opposite direction. This difference in apparent density results in different indices of refraction for light moving in opposite directions allowing the researchers to pass light of the same frequency down the fibre from both ends and enable light transmitting from one side but block from the other. Wavelengths that are off resonance with the cavity will be transmitted; wavelengths on resonance with the cavity are absorbed. The device could find use in optical circuits… read more. Open Access TECHNICAL ARTICLE 

One-way system: researchers find new way to stop light from propagating in the wrong direction. (Courtesy: Shutterstock/Shibiko)