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arXiv:quant-ph/0210023 · Physical Review A

Experimental study of the spatial distribution of quantum correlations in a confocal optical parametric oscillator

M. Martinelli, Nicolas Treps, S. Ducci, Sylvain Gigan, Agnès Maître, Claude Fabre

Published Feb 13, 2003• 56 citations
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Abstract

We study experimentally the spatial distribution of quantum noise in the twin beams produced by a type-II optical parametric oscillator operating in a confocal cavity above threshold. The measured intensity correlations are at the same time below the standard quantum limit and not uniformly distributed inside the beams. We show that this feature is an unambiguous evidence for the multimode and nonclassical character of the quantum state generated by the device.

DOI
10.1103/physreva.67.023808

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We study experimentally the spatial distribution of quantum noise in the twin beams produced by a type-II optical parametric oscillator operating in a confocal cavity above threshold. The measured intensity correlations are at the same time below the standard quantum limit and not uniformly distributed inside the beams. We show that this feature is an unambiguous evidence for the multimode and nonclassical character of the quantum state generated by the device.
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The visibility and quality of optical images is ultimately limited not by diffraction but by the quantum noise affecting each pixel of a detector. Multimode non-classical states of light, characterized by spatial quantum correlation or local reduced quantum noise, permit in principle to go beyond the standard quantum limit and therefore to improve transverse optical resolution. It has been predicted that Optical Parametric Oscillators (OPO) operating simultaneously on many transverse modes are good candidates for generating multimode non-classical states of light. We perform an experiment showing that a c.w. confocal OPO above threshold emits such states. Below threshold, the OPO is turned to a multimode optical parametric amplifier.
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