Polarization Squeezing Research Articles

Polarization squeezing of intense pulses with a fiber-optic Sagnac interferometer

We report on the generation of polarization squeezing of intense, short light pulses using an asymmetric fiber-optic Sagnac interferometer. The Kerr nonlinearity of the fiber is exploited to produce independent amplitude squeezed pulses. The polarization squeezing properties of spatially overlapped amplitude squeezed and coherent states are discussed. The experimental results for a single-amplitude squeezed beam are compared to the case of two phase-matched, spatially overlapped amplitude squeezed pulses. For the latter, noise variances of $\ensuremath{-}3.4\mathrm{dB}$ below shot noise in the ${S}_{0}$ and the ${S}_{1}$ and of $\ensuremath{-}2.8\mathrm{dB}$ in the ${S}_{2}$ Stokes parameters were observed, which is comparable to the input squeezing magnitude. Polarization squeezing, that is, squeezing relative to a corresponding polarization minimum uncertainty state, was generated in ${S}_{1}.$

Polarization squeezing and continuous-variable polarization entanglement

The Stokes-parameter operators and the associated Poincare sphere, which describe the quantum-optical polarization properties of light, are defined and their basic properties are reviewed. The general features of the Stokes operators are illustrated by evaluation of their means and variances for a range of simple polarization states. Some of the examples show polarization squeezing, in which the variances of one or more Stokes parameters are smaller than the coherent-state value. The main object of the paper is the application of these concepts to bright squeezed light. It is shown that a light beam formed by interference of two orthogonally-polarized quadrature-squeezed beams exhibits squeezing in some of the Stokes parameters. Passage of such a primary polarization-squeezed beam through suitable optical components generates a pair of polarization-entangled light beams with the nature of a two-mode squeezed state. The use of pairs of primary polarization-squeezed light beams leads to substantially increased entanglement and to the generation of EPR-entangled light beams. The important advantage of these nonclassical polarization states for quantum communication is the possibility of experimentally determining all of the relevant conjugate variables of both squeezed and entangled fields using only linear optical elements followed by direct detection.

Polarization squeezing of continuous variable stokes parameters.

We report the first direct experimental characterization of continuous variable quantum Stokes parameters. We generate a continuous wave light beam with more than 3 dB of simultaneous squeezing in three of the four Stokes parameters. The polarization squeezed beam is produced by mixing two quadrature squeezed beams on a polarizing beam splitter. Depending on the squeezed quadrature of these two beams the quantum uncertainty volume on the Poincaré sphere becomes a "cigarlike" or "pancakelike" ellipsoid.

Formation and conversion of the polarization-squeezed light

Abstract We consider polarization-squeezed (PS) light generation in anisotropic Kerr medium. The fluctuations of the Stokes parameter either S 2 or S 3 are suppressed in PS light. We show the possibility to transform PS light into light with sub-Poissonian statistics by linear conversion (phase plate and analyser). The quantum properties of the second harmonic (SH) generated by frequency doubling of the PS light are investigated.

Polarization squeezing and new states of light in quantum optics

The concept of squeezing is discussed for multimode quantum light beams with the consideration of polarization using the polarization gauge SU (2) invariance of free electromagnetic fields. We separate the polarization degrees of freedom from other ones, and consider uncertainty relations characterizing polarization observables. As a consequence, we obtain a new classification of polarization states of light within quantum optics.