ON THE PROPAGATION OF SHORT OPTICAL PULSES IN A LINEAR DISPERSIVE MEDIUM WITH ABSORPTION

A very accurate numerical algorithm based on the Laplace transform is used to describe the field evolution of ultrashort Gaussian-modulated pulses in a single resonance Lorentz medium. The results are compared with previously published numerical results in which a simple Taylor series expansion of the input pulse spectrum about the carrier frequency is employed to explain the observed pulse dynamics. It is shown here, by numerical Laplace transform analysis, that these previously published numerical results are inaccurate and that the first few terms of the Taylor series expansion technique about the carrier frequency do not properly explain the physically correct dispersive pulse evolution properties for rapid rise time pulses. Accurate examples of dispersive pulse propagation of ultrashort Gaussian pulses are presented.