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.