MEASUREMENT OF QUANTUM-NOISE CORRELATIONS IN PARAMETRIC IMAGE AMPLIFICATION

We demonstrate quantum-noise correlations between the spatial frequenc ies of a parametrically amplified signal image and the generated conju gate (idler) image. Test images were amplified by an optical parametri c amplifier that can be operated either as a low-pass or a band-pass a mplifier for spatial frequencies. Direct difference detection of the s ignal and idler spatial frequencies at +/-16 mm(-1) resulted in noise that fell below the shot-noise level by similar or equal to 5 dB. Para metric-gain and phase-mismatch dependence of the observed quantum-nois e reduction is in good agreement with the theory of a spatially-broadb and optical parametric amplifier. (C) 1998 Optical Society of America.