Pulsemode expansions and refractive indices in planewave propagation
Abstract
This memo presents basic background theory for treating simultaneous propagation of electromagnetic pulses of various colors, directed along a common ray, through a molecular vapor. The memo discusses some techniques for expanding the positive frequency part of the transverse electric field into pulse modes, characterized by carrier frequencies within a modulated envelope. We discuss, in the approximation of plane waves with slowly varying envelopes, a set of uncoupled envelope equations in which a polarization modeenvelope acts as a source for an electricfield envelope. These equations, when taken with a prescription for the polarization field, are the basic equations of planewave pulse propagation through a molecular medium. We discuss two ways of treating dispersive media, one based upon expansions in the frequency domain and the other based in the time domain. In both cases we find envelope equations that involve group velocities. This memo represents a portion of a more extensive treatment of propagation to be presented separately. Many of the equations presented have been described before. They are treated here as a summary and review of contemporary theory been described in various books and articles. They are collected and described here as a summary and review of contemporary theory.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 June 1987
 Bibcode:
 1987STIN...8812714S
 Keywords:

 Expansion;
 Plane Waves;
 Refractivity;
 Wave Equations;
 Wave Propagation;
 Electromagnetic Pulses;
 Fourier Analysis;
 Magnetic Fields;
 Communications and Radar