Coherent control of the polarization of ultrashort optical pulses using electromagnetically induced transparency

We propose a scheme of all-optical polarization switching in a four-level atomic system. In this scheme, the polarization state of an optical pulse is controlled by an another control pulse via a four-wave mixing (FWM) process between orthogonal components of a pulse. Using a sufficiently strong control pulse, a linear absorption loss during FWM is significantly suppressed, therefore the polarization can be controlled with high transmission efficiency. Since our scheme requires only one ground (stable) state, it is applicable to the excitonic systems of semiconductor quantum wells. Our numerical calculation, based on typical parameters of Pb-based inorganic-organic-layered perovskite-type materials, shows that, using ultrashort-pulse trains, polarization switching with a high repetition rate of more than 10 GHz is possible.