Ultrashort Pulse Propagation in Negative Index Materials: From Negative Refraction to Nonlinear Pulse Propagation

摘要

Negative index materials (NIMs) hold the promise for super lensing of electromagnetic radiation for applications in radar, THz, and possibly at optical frequencies. We have developed a new vector pulse propagation method that we use to study the electrodynamics of negative index materials (NIMs). Although numerous papers have been published on the unusual properties of NIMs, we are the first to apply a propagation model to the problem. As we will show in the figures below, our propagation model provides added insight to the dynamics compared with the plane wave work published to date. In addition, the concept of index of refraction is not an explicit quantity found within Maxwell s field equations, and for this reason we resort only to the concepts of dielectric susceptibility e and magnetic permeability m. We thus numerically solve Maxwell's equations and show that a vector field indeed undergoes negative refraction (the beam is bent as if the index of refraction were negative) upon crossing an interface between vacuum and a medium where both e and m are negative and real, following a Drude model of both e and m. On the other hand, we show that if the medium is thought of as a collection of Lorentz oscillators, then absorption completely destroys the process within a propagation depth of only a fraction of a wavelength.