Modulating the multi-wave mixing processes via the polarizable dark states

Controllable switch of a transmittance signal via polarization combination manipulation

We propose and experimentally demonstrate a process in which we can control the behavior of an atomic medium to switch on or off transmittance signals at multiple frequencies in ladder-type electromagnetically induced transparency (EIT) of 5S_1/2-5P_3/2-5D_3/2 transition of Rb87 atoms. By adjusting the polarizations of the applied optical fields, the amplitudes of the transmittance spectra at multiple frequency channels can be controlled. This mechanism originates from the competition between EIT subsystems and single-photon absorption with a contribution from different transition strengths. Moreover, we also analyze the influences of the intensity and detuning of the coupling field on the transmitted signals when two lasers are perpendicular, linearly polarized lights, and observe electromagnetically induced absorption due to quantum constructive interference. Detailed theoretical analyses, including the different strengths in different transitions and Doppler broadening, agree with the experimental observations.

Modulating the correlation and squeezing of phase-conjugate four-wave mixing via the polarizable dressing states

We report the experimental observation of the intensity noise correlation and squeezing between counter propagating Stokes and anti-Stokes signals in Pr(3+):Y2SiO5 crystals. Both the degree of correlation and squeezing as well as the oscillation frequency of correlation curves are modulated by changing the polarization states and powers of the dressing fields. The double-dressed effect and the triple-dressed effect in V-type three-level, Λ-type three-level and N-type four-level systems are compared. The polarization and power dependencies in these systems are different, and the oscillation frequency of the correlation curve in the triple-dressed process is greater than that of the double-dressed process. Our results show that the correlation and squeezing of photon pairs can be controlled via polarized dark states.