Application of Mueller Matrix and Near Fields Measurements to Detect and Identify Trace Species in Drugs and Threat Agents

摘要

Since biological materials possess some degree of chirality a full wave solution for the scattering of electromagnetic waves (including optical and infra-red wavelengths) at an irregular interface between free space and a chiral medium is derived. To this and the electromagnetic fields are expressed in terms of Generalized Fourier Transforms. These transforms provide the basis for converting Maxwells equations, together with the associated exact boundary conditions, into Gneralized Telegraphists' Equations for irregular stratified media. Scattered near fields as well as far fields can be obtained from the solutions for the Generalized Telegraphists equations. The Mueller elements are related to the linear like and cross polarized far field scattering matrix. All sixteen Mueller Matrix elements of Bio-Medical Materials are examined. Special attention is given to the eight quasi off diagonal elements of the Mueller Matrix in order to examine the feasibility for detection and identification of bio-medical materials. The specific impact of chirality on the Mueller Matrix elements is analyzed. It is shown that (to within first order of the chirality parameter) only the eight quasi off diagonal elements of the Mueller Matrix are effected by the chiral property of the bio-medical materials. This reinforces the experimental observation from previous scattering experiments that the quasi off diagonal Mueller Matrix elements could provide a basis for bio-medical detection and identification. The analysis provides the explicit relationship between the quasi off diagonal elements and the degree of chirality of the bio-medical materials.