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O. Haderka

Publications and source records attributed to O. Haderka.

4 recordsLinked to original sources

Coherence properties of high-gain twin beams generated in pump-depletion regime

Twin-beam coherence properties are analyzed both in the spatial and spectral domains at high-gain regime including pump depletion. The increase of the size of intensity auto- and cross-correlation areas at increasing pump power is replaced by a decrease in the pump depletion regime. This effect is interpreted as a progressive loss in the mode selection occurring at high-gain amplification. The experimental determination of the number of spatio-spectral modes from $g^{(2)} $-function measurements confirms this explanation.

quant-ph

Statistical properties of twin beams generated in spontaneous parametric downconversion

Measurement of photon-number statistics of fields composed of photon pairs generated in spontaneous parametric downcoversion pumped by strong ultrashort pulses is described. Final detection quantum efficiencies, noises as well as possible loss of one or both photons from a pair are taken into account. Measured data provided by an intensified single-photon CCD camera are analyzed along the developed model. The joint signal-idler photon-number distribution is obtained using the expectation maximization algorithm. Covariance of the signal and idler photon-numbers equals 80 %. Statistics of the generated photon pairs are identified to be Poissonian in our case. Distribution of the integrated intensities of the signal and idler fields shows strong correlations between the fields. Negative values of this distribution occurring in some regions clearly demonstrate a nonclassical character of the light composed of photon pairs.

quant-ph

Multiple-photon resolving fiber-loop detector

We show first reconstructions of the photon-number distribution obtained with a multi-channel fiber-loop detector. Apart from analyzing the statistics of light pulses this device can serve as a sophisticated postselection device for experiments in quantum optics and quantum information. We quantify its efficiency by means of the Fisher information and compare it to the efficiency of the ideal photodetector.

quant-ph

Testing operational phase concepts in quantum optics

An experimental comparison of several operational phase concepts is presented. In particular, it is shown that statistically motivated evaluation of experimental data may lead to a significant improvement in phase fitting upon the conventional Noh, Fouge'res and Mandel procedure. The analysis is extended to the asymptotic limit of large intensities, where a strong evidence in favor of multi--dimensional estimation procedures has been found.

quant-ph