Evolution of Sommerfeld and Brillouin precursors in intermediate spectral regimes

Journal article, 2009

We study, numerically, the transitional behavior of precursors in the intermediate spectral regime between two contrasting regimes for which analytical solutions exist. The two opposite regimes are, respectively, defined as (1) off-resonance carrier with a spectral pulse width comparable to the medium’s absorption linewidth and (2) on-resonance carrier with the spectral width of the pulse much narrower than the absorption linewidth. Beyond these two regimes, there have been few studies of precursors. In this paper, we investigate precursor dynamics for the intermediate spectral regime using the finite-difference time domain method. The parameter that has the strongest influence on the precursor dynamics is found to be the plasma frequency, ωp. This research is applicable for controlling transients in fast communication systems.