Nonstationary elliptically polarized normal modes of electromagnetically induced transparency

The results of analytical and numerical analysis of propagation of short probe pulses of electromagnetically induced transparency in the case of control field elliptic polarization are presented. The situation is explored, when the probe field is weak in comparison with the control radiation. Then the probe pulse in the medium is a sum of two elliptically polarized pulses, which travel without interaction with each other and have invariable states of polarization. This fact permits to refer these pulses to as nonstationary elliptically polarized normal modes. Numerical simulation showed, that normal mode structure is determined by the ratio of spectral width of input probe pulse to spectral width of quantum transition, which is resonant to the probe emission. When this ratio is small, each mode in the medium is a pulse similar to input probe pulse. If this ratio is large, the mode envelopes are distorted, when the mode pulses travel in the medium. In this case, the probe pulse absorption increases considerably. The theoretical investigation is performed for the A-scheme of degenerate quantum transitions between P-3(0), P-3(1)0 and P-3(2) energy levels of Pb-208 isotope.