Parsing polarization squeezing into Fock layers
C. Müller, Lars S. Madsen, A. B. Klimov, Luis Lorenzo Sánchez-Soto, Gerd Leuchs, Christoph W. Marquardt, Ulrik L. Andersen · Physical Review A · 2016
We investigate polarization squeezing in squeezed coherent states with varying coherent amplitudes. In contrast to the traditional characterization based on the full Stokes parameters, we experimentally determine the Stokes vector of each excitation subspace separately. Only for states with a fixed photon number do the methods coincide; when the photon number is indefinite, we parse the state in Fock layers, finding that substantially higher squeezing can be observed in some of the single layers. By capitalizing on the properties of the Husimi $Q$ function, we map this notion onto the Poincar\'e space, providing a full account of the measured squeezing.