Spatial overlap of nonclassical ultrashort light pulses and formation of   polarization-squeezed light
  We investigate the spatial overlap of nonclassical ultrashort light pulses produced by self-phase modulation effect in electronic Kerr media and its relevance in the formation of polarization-squeezed states of light. The light polarization is treated in terms of four quantum Stokes parameters whose spectra of quantum fluctuations are investigated. We show that the frequency at which the suppression of quantum fluctuations of Stokes parameters is the greatest can be controlled by adjusting the linear phase difference between pulses. By varying the intensity of one pulse one can suppress effectively the quantum fluctuations of Stokes parameters. We study the overlap of nonclassical pulses inside of an anisotropic electronic Kerr medium and we show that the cross-phase modulation effect can be employed to control the polarization-squeezed state of light. Moreover, we establish that the change of the intensity or of the nonlinear phase shift per photon for one pulse controls effectively the squeezing of Stokes parameters. The spatial overlap of a coherent pulse field with an interference pulse produced by mixing two quadrature-squeezed pulses on a beam splitter is analyzed. It is found that squeezing is produced in three of the four Stokes parameters, with the squeezing in the first two being simultaneous. 
F. Popescu