Pulse-induced radiation in the linear regime

E G Lariontsev, I.P. Skuybina

B.I. Bondarev

Oleg M. Parshkov, Ekaterina R. Govorenko

Results of numerical analysis of the influence of probe pulse duration on the character of its evolution under the conditions of electromagnetically induced transparency in a Λ-scheme involving degenerate quantum transitions are presented. The cases of weak and strong input probe pulses linearly polarized in the same direction as the polarized coupling radiation, along with the case of linearly polarized probe radiation and circularly polarized coupling radiation, are considered. Calculations showed that the regime of weak probe radiation is most favorable for formation of a short probe pulse with a duration of about 1 ns and pulse shape that does not change substantially upon pulse propagation. However, even in this case, picosecond probe pulses experience considerable deformation of their shape and loss of power. Considerable changes of the pulse shape in the case of a strong probe pulse occur already when the pulse duration approaches 1 ns. This circumstance can limit the response time of prospective devices based on the effect of electromagnetically induced transparency.

Oleg M. Parshkov

The evolution of radiation under conditions of electromagnetically induced transparency in the scheme of degenerate quantum transitions J = 0 → J = 1 → J = 2 in the pulsed interaction regime of the fields and with allowance for the Doppler broadening of spectral lines has been analyzed numerically. It has been shown that, if the input coupling radiation is linearly polarized, the circularly polarized input probe pulse splits in the medium into pulses with mutually perpendicular linear polarizations. The direction of polarization of one of these pulses coincides with the direction of polarization of the input coupling field. The distance that the probe pulse travels in the medium until it completely decays decreases with a decrease in both the duration of the input probe pulse and the intensity of the input coupling radiation. A change in the power of the input probe pulse hardly affects the distance required for the decay and the velocity of propagation of linearly polarized pulses in the medium. An increase in the Doppler broadening of spectral lines leads to a decrease in this distance and, simultaneously, to an increase in the energy losses of the probe radiation. Qualitative considerations that explain the physical reason for the investigated effects have been presented.

R. Bullough

M. T. Turaev