Propagation of the phase pulses of bichromatic radiation under the electromagnetically induced transparency conditions

We study the dynamics of the phase pulses of laser radiation with two resonant frequency components propagating in an atomic three-level. type medium under coherent population trapping. Using the density matrix adiabatic approach we show that the effect of a very large slowing down occurs not only for amplitude pulses, but also for phase pulses. The group velocity of phase pulses can be controlled by the amplitudes of resonant fields. The analytical solution describing the mutual influence of the phase modulation of one field component on another is obtained.