Resonant scattering for characterization of axisymmetric dielectric objects

Resonances in the electromagnetic scattering by dielectric objects are investigated both numerically and experimentally with particular emphasis on their direct application to object characterization. Low ka calculations for spheres and an infinite circular cylinder illustrate the modal nature of the resonances and the dependence of the resonance spectra on refractive index and size. Experiments show that the specific wavelengths at which resonances occur in the scattering intensity from a glass fiber can be used to determine its diameter to a high accuracy. The extended boundary condition method is used to calculate the low ka resonances of a prolate spheroid and a finite circulate cylinder with the anticipation that the scattering resonances may be particularly suitable for characterizing randomly oriented nonspherical objects.