Vavilov-Cerenkov phenomenon in metal nanofilms

TL;DR

This paper explores the Vavilov-Cerenkov effect in metal nanofilms, showing that electrons can emit Cerenkov radiation via surface plasmon polaritons with low phase velocities, expanding understanding of light emission in nanostructures.

Contribution

It demonstrates that Cerenkov radiation can occur in nanofilms through surface plasmons with low phase velocities, providing new insights into light emission mechanisms at the nanoscale.

Findings

Cerenkov emission occurs in nanofilms via surface plasmons.

Dispersion relations for plasmons are calculated.

Angles of emission are determined for different frequencies.

Abstract

The Vavilov-Cerenkov phenomenon - light emission during the motion of a fast electron in a dense medium is observable in homogeneous media as well as in inhomogeneous media like photonic crystals. So long as a space (homogeneous or inhomogeneous) contains natural waves with phase velocities that are lower than the velocity of a flying through electron then a Cerenkov emission of light would appear. In nanofilms and nanowires made of silver, gold, copper there are so called surface plasmon polaritons, namely natural waves with a low phase velocity. These waves velocity could be by tens and hundreds times lower than the light velocity in vacuum. An electron with a velocity that is comparatively lower than a velocity of an electron that is able to emit in a uniform medium could emit Cerenkov light. Dispersion relations are calculated for the corresponding plasmons as well as the angles of emission of the plasmons of corresponding frequencies.