Analysis of optical focused electromagnetic field by a parabolic reflector coated with a plasma layer under normal incidence

摘要

A theoretical investigation has been carried out to analyze the focusing of electromagnetic field by a parabolic reflector coated with a plasma layer under normal angle of incidence. The reflection and transmission coefficients at dielectricplasma and plasma-perfect electric conductor interfaces are derived analytically. The focal region electromagnetic field expressions have been obtained using Maslov's method. The derived analytical field expressions at caustic or focal point of plasma coated parabolic reflector have been solved numerically using MATHEMATICA. The effects of some physical parameters such as the plasma and wave frequencies and the thickness of plasma layer on the focal regions reflected and transmitted field from plasma layer are studied. The comparisons of the computed results of the presented formulations with the published results of some special cases confirm the accuracy of the presented analysis.