Quantum Reconstruction of an Intense Polarization Squeezed Optical State

We perform a reconstruction of the polarization sector of the density matrix of an intense polarization squeezed beam starting from a complete set of Stokes measurements. By using an appropriate quasidistribution, we map this onto the Poincaré space, providing a full quantum mechanical characterization of the measured polarization state.

Figure 1

Setup for efficient polarization squeezing generation and the corresponding Stokes measurement apparatus.

Figure 2

Measured histograms of the difference current of the two detectors for various measurement angles on the Poincaré sphere. When the total number of photons is not measured, the histograms are the sum over $J$ of the tomograms (3). Note the different scales on both plots. Histograms 1, 2, and 3 are in the dark plane, while histogram 5 is at the classical mean value. The histograms corresponding to electronic and shot noise are also shown.

Figure 3

Sections of the isocontour surface plots of the $Q$ function for a coherent state (blue) and a polarization squeezed state (red).

Figure 4

Probability distribution $Q(\mathbf{n})$ over the Poincaré unit sphere for a polarization squeezed state obtained over all invariant subspaces. The distribution is strongly concentrated at the classical mean value, so we show a zoomed version.