Numerical simulation of optical nutations and a precursor pulse in electromagnetically induced transparency

The results of numerical simulation of the electromagnetically induced transparency phenomenon in the ?? scheme of degenerate quantum transitions J = 0 ?? J = 1 ?? J = 2 with Doppler broadening of spectral lines are presented for the cases of continuous and abrupt rises in the leading edge of the input probe radiation pulse. For circularly polarized radiations, it has been shown that the deviation from the condition of adiabatic sequence can lead to a separation of the probe pulse of the adiabaton into a train of subpulses. In the case of linear polarization of the input probe field and the circular polarization of the input control field, the probe radiation pulse is split into two pulses with opposite circular polarizations and a multispike structure of the envelopes. In the case of an abrupt rise in the leading edge of the input probe pulse, regardless of the peak intensity of the latter, the precursor pulse arises at a probe radiation frequency and the velocity of its propagation coincides with the speed of light in vacuum.