QUANTUM-NONDEMOLITION MEASUREMENTS AND GENERATION OF INDIVIDUALLY SQUEEZED TWIN BEAMS BY A DEGENERATE OPTICAL PARAMETRIC-AMPLIFIER

A novel scheme for continuous-wave quantum nondemolition (QND) detecti on of optical-amplitude quadratures is implemented using a degenerate optical parametric amplifier. A monolithic ring resonator with optimiz able frustrated total internal reflection coupling is used. Signal and meter output beams are squeezed by 0.5 dB and 2.2 dB, and 38% correla ted. This implies the first realization of individually squeezed twin beams, as well as quantum state preparation ability for both output be ams. A quantum optical tap efficiency T-s + T-m = 1.08 is achieved. Th e all-solid-state system was completely stabilized and continuously op erated as a QND device for up to 36 hours.