Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Observation of noiseless parametric amplification of images

It is well-known that parametric amplification can amplify a signal without degrading it (noise figure equal to 1), provided that it operates in a phase sensitive configuration. In a work performed before the beginning of the QUANTIM project, the NWU group had experimentally shown that this was the case (within the experimental imperfections) for the temporal fluctuations measured at the different points of an image.

UFC, using its recognized expertise on the parametric amplification of images, has studied the pixel to pixel spatial fluctuations on a single shot amplified image by a pulsed, type I, frequency degenerate optical parametric amplifier. The spatial noise figures were experimentally determined in the phase-sensitive and phase insensitive schemes. Both are in good agreement with theory, and UFC recently showed that, as expected, and in the low gain regime, the phase sensitive amplifier does not add noise, while the phase insensitive amplifier leads to the classical 3 dB degradation of the signal to noise ratio.

The experiment and the data processing are very delicate, because of the low level of the signal on each pixel, the absence of the relative phase control and problems of wavefront. They will be improved in the near future in order to observe more easily the quantum spatial effect, and to use it in applications.

Reported by

ENS Laboratoire Kastler Brossel
UPMC Case 74
75252 Paris