Very slow surface plasmons: theory and practice

TL;DR

This paper reviews the theory and practical applications of very slow optical surface plasmons, highlighting their role in electromagnetic modes, photon momentum, and advanced optical imaging techniques.

Contribution

It broadens the understanding of electromagnetic modes and photon momentum in plasmonic systems, integrating recent experimental and theoretical developments.

Findings

Enhanced control of photon momentum in plasmonic structures

Demonstration of sub-diffraction optical focusing

Advancements in optical imaging beyond diffraction limits

Abstract

The paper is of a methodological character and has as a goal to give a brief description of the concept of theory and practical application of very slow optical plasmons. They exist on the metal-dielectric boundaries, namely, on very thin metal films and fibers and as standing waves on metal spheres and ellipsoids. The material presented in the paper features by widening the common concepts of electromagnetic modes of various spaces, of the probability of spontaneous emission, of creation of optical images, of the limits of optical focusing, and of the photon linear momentum. All mentioned studies are completed in recent years. The problem of the photon momentum in a dielectric medium was the topic of irreconcilable disputes for 100 years starting in the time of appearing of Minkowski and Abraham famous papers. Various practical applications are surveyed: the experiments with a great intensification of an atom spontaneous emission into a plasmonic field mode of a metal nanoparticle, the experiments on focusing optical radiation into a spot that substantially smaller than a diffraction limited spot, a so called near perfect Pendry lens that produces the image with details that substantially smaller than defined by diffraction, and lastly, the concept of hundredfold and more magnification of a photon mechanical linear momentum in a plasmon. The work completed is supported by RFBR, grants Nos 05-02-19647, 07-02-01328.