The accuracy of the group-velocity description of dispersive pulse propagation in a double-resonance Lorentz model dielectric is shown to decrease monotonically as the propagation distance increases, whereas the accuracy of the asymptotic description increases monotonically as the propagation distance increases above a single absorption depth in the medium at the pulse carrier frequency.
© 1999 Optical Society of America
Hong Xiao and Kurt E. Oughstun, "Failure of the group-velocity description for ultrawideband pulse propagation in a causally dispersive, absorptive dielectric," J. Opt. Soc. Am. B 16, 1773-1785 (1999)