About Propagation of Gaussian Electromagnetic Pulse in a Resonantly Absorbing Gas Medium

Based on direct and without simplifying assumptions calculation of the Fourier integral, the analysis of the process of the passage of terahertz pulses with Gaussian envelope and amplitude spectrum belonging to the frequency interval occupied by the spectral line, through the layer of resonantly absorbing medium was made. The interaction of the medium and the pulse is described by Drude-Lorenz model. It is shown that with an increase in the optical depth of the medium layer, the current envelope of the radiation field recorded at the receiving end of the path is increasingly affected by the interference effect of harmonics of individual sections of the current pulse spectrum, which leads to its fundamental deformation, but not to its systematic shift towards negative time values. Analysis of the integral characteristics of the received radiation field also does not agree with the conclusions corresponding to the first approximation of the dispersion theory. Methods are proposed for eliminating oscillations of the envelope of the received pulse by shifting the carrier and changing the bandwidth of the receiving device.

resonantly absorbing medium, Gaussian pulse, envelope deformation