Hardware for a quantum network

Abstract

An optomechanical device has been designed that converts radio-frequency electrical signals into laser light. The system could allow computers to share data in a future quantum network based on optical fibres. See Letter p.81 Many applications, from medical imaging and radio astronomy to navigation and wireless communication, depend on the faithful transmission and detection of weak radio-frequency microwaves. Here Eugene Polzik and co-workers demonstrate a completely new capability in this area — the conversion of weak radio waves into laser signals using a nanomechanical oscillator. The oscillator, a membrane made from silicon nitride, can couple simultaneously to radio signals and light reflected off its surface and this feature can be used to measure the radio signals as optical phase shifts, with quantum-limited sensitivity. Compared to existing detectors, this approach has the advantage of working at room temperature, and the signals produced can be readily transferred into standard optical fibres.