Back action evading electro-optical transducer

Electro-optical transducers are utilized for upconvertion of radio frequency (RF) signals to the optical frequency domain to study the RF signals with optical tools. The transducers frequently impact on the RF system and introduce additional noise, including optical shot noise as well as quantum back action noise, limiting the measurement accuracy. In this paper we theoretically study a technique based on a high efficiency electro-optical phase modulation effect that allows back action evading detection of an RF field quadrature. The main idea of proposed method is independent homodyne detection of two (Stokes and anti-Stokes) optical modes. It allows subsequent postprocessing of the detected signals, which, in turn, results in a broadband back action evading measurement leading to the high sensitivity evaluation of the RF signals.