- Wong, Ngai C. and Leong, K. W. and Shapiro, Jeffrey H., Nonclassical intensity correlation from a type I phase matched optical parametric oscillator
pp. 68 - 70 .
(last updated on 2007/04/13)
The observation of nonclassical correlation in the intensities of the nondegenerate signal and idler outputs from an optical parametric oscillator (OPO) is reported. The CW OPO consists of a 25-mm-long, type-I, phase-matched LiNbO3:MgO crystal inside a single-ended cavity, which is resonant for both the signal and idler. The output coupling for the IR signal and idler is approximately 4.5%, and the internal round trip power loss is estimated to be 1.9%. The detected signal and idler are amplified, differenced, and compared to the shot-noise level provided by two light bulbs having the same DC photocurrents. A broadband intensity correlation is observed over a frequency range from 0.8 to 5 MHz. The maximum correlation, which occurs at approximately 1.5 MHz, yields a noise level 45% below shot noise. The estimated system efficiency of 83% then implies a generated noise suppression of 55%. Below 800 kHz, the difference intensity noise is dominated by 1/f-type excess noise. A linearized quantum analysis of the doubly resonant OPO, including the effects of the pump noise, shows that at low frequencies the pump noise may impose a limit on the maximum noise suppression.
Oscillators;Noise, Spurious Signal--Shot Noise;Quantum Theory;