%0 Journal Article
%T Generation of Bessel Surface Plasmon Polaritons in a Finite-Thickness Metal Film
%A S. N. Kurilkina
%A V. N. Belyi
%A N. S. Kazak
%J International Journal of Optics
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/253692
%X A theory of generation of low- and high-index Bessel surface plasmon polaritons and their superposition in a metal film of a finite thickness is developed. Correct analytical expressions are obtained for the field of two families of Bessel surface plasmon polariton modes formed inside and outside the metal layer. The intensity distribution near the boundary of the layer has been calculated and analyzed. A scheme for the experimental realization of a superposition of Bessel surface plasmon polaritons is suggested. Our study demonstrates that it is feasible to use the superposition of Bessel surface plasmon polaritons as a virtual tip for near-field optical microscopy with a nanoscale resolution. 1. Introduction Surface plasmon polaritons (SPPs) are surface electromagnetic waves related to collective electron oscillations near the metal surface excited by light [1¨C3]. These fields arise under the resonance condition, and due to such nature of excitation, they are attractive in the context of enhancing the resolution of imaging systems substantially by increasing the amplitude of evanescent waves [4¨C6]. In 1987, Durnin et al. suggested a new type of waves, namely, Bessel light beams (BLBs), that kept the transverse spot size unchanged much longer than the Rayleigh range [7, 8]. Such a localized radiation mode was called the nondiffracting beam (or the diffraction-free beam). The transverse profile of the amplitude of this beam is described by a Bessel function of the first kind. In the domain of spatial frequencies, BLB is represented as a superposition of plane waves which are wrapped around a conical surface. Within the last decades, an intensive study of the scalar and vector BLBs has been made theoretically and experimentally (see, e.g., [9¨C18]). Bessel light beams are used in numerous applications, such as the optical manipulation of microsized particles [19], the fabrication of long polymer fiber induced by the photopolymerization [20] and microchanneling by structural modification in glass materials [21] the enhancement of energy gain in inverse-free electron lasers and inverse Cherenkov accelerators [22]. The authors of [23] pioneered in obtaining solutions of Maxwell¡¯s equations which correspond to evanescent BLBs formed in the condition of the internal total reflection in an optically less dense dielectric medium. A more detailed theory of evanescent Bessel beams is presented in [24¨C29]. These beams exponentially decay while moving off the surface but retain their original transversal shape. In those investigations, of particular interest was the
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