Quantum Enhancement of Phase Sensitivity for the Bright-Seeded SU(1,1) Interferometer with Direct Intensity Detection
Shengshuai Liu, Yanbo Lou, Jun Xin, Jietai Jing · Physical Review Applied · 2018
SU(1,1) interferometers, based on nonlinear optical processes, potentially offer better phase sensitivity than traditional instruments. Bright-seeded variants are important for applications with large numbers of photons, yet have remained uncharacterized experimentally, for lack of a real-time technique to measure phase sensitivity. This study uses a direct intensity-detection technique to demonstrate the quantum enhancement of phase sensitivity in real time for a bright-seeded SU(1,1) system, compared to the classical shot-noise limit. It is hoped that these results will promote applications of this class of interferometer in quantum metrology.