Field detection by subwavelength aperture probes

Abstract

In this paper we consider the coupling of energy from electromagnetic waves through an electrically small aperture into a tapered metallic probe. An understanding of propagation through an aperture is essential if subwavelength resolution near-field studies of diffraction patterns are to be performed. Small-hole coupling theory is used to determine the total power transmitted into a perfectly conduction conical waveguide which approximates a tapered probe. It is found that along with the size of the coupling aperture, the most significant factor in determining the transmitted power is the radius of the waveguide at the point of coupling.