Quantum polarization tomography of bright squeezed light

Abstract

We reconstruct the polarization sector of a bright polarization squeezed beam starting from a complete set of Stokes measurements. Given the symmetry that underlies the polarization structure of quantum fields, we use the unique SU(2) Wigner distribution to represent states. In the limit of localized bright states, the Wigner function can be approximated by an inverse threedimensional Radon transform. We compare this direct reconstruction with the results of a maximum likelihood estimation, thus finding excellent agreement. Figure 4. Sections of the isocontour of the Wigner function in figure 3 through the coordinate axes, for the three different reconstruction techniques used. In gray the direct Radon transform, in green the ML method with nine settings for the angles of the wave plates and in dotted lines the results of a Gaussian ML approximation are shown.

Multipolar hierarchy of efficient quantum polarization measures

“…However, the appearance of hurdles such as hidden polarization [15], the fact that the Poincaré sphere cannot accommodate photon-number fluctuations [16], and the difficulties in defining polarization properties of two-photon entangled fields [17], to cite only a few examples, show that the resulting theory is insufficient.…”

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“…In the bottom panel we include the views of the parsed Husimi function along the three coordinate axes for the state with α = 2.31. The typical cigarlike projections, familiar from previous measurements [27], can be recognized.…”

Generation of optical-terahertz biphoton pairs via spontaneous parametric down-conversion

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