A combination of a four-level electromagnetically induced transparency and second-order nonlinearity is shown to enhance profoundly the efficiency of frequency conversion in an Er-doped glass owing to the pump-pulse slowing down.
We report the experimental observation of a slow-light information conversion via electromagnetically induced transparency (EIT) in a rare-earth-ion-doped solid. Under the EIT-based slow-light regime, by manipulating the spectrum of the control fields, the slowed light pulse is transformed into two different frequency-spatial channels. The pulse shapes and energies in two output channels are further studied. This slow-light information conversion can be used as a controllable frequency-spatial multiplexing of the quantum state of the optical field and will be important in information processing and all-optical networks.
A time-dependent perturbation calculation for a four-level system is presented. A resonantly enhanced Kerr nonlinearity is produced with a combination of long, short, and delayed laser pulses in the presence of electromagnetically induced transparency. We show the enhanced Kerr nonlinearity and vanishingly small linear susceptibility due to the induced transparency, both are favorable for cross-phase modulation. In addition, we show that possible constructive and destructive interference between different excitation pathways could also lead to enhancement and suppression of the Kerr nonlinearity.