Spontaneous radiation of a finite-size dipole emitter in hyperbolic media

TL;DR

This paper investigates how a finite-size dipole emitter's spontaneous radiation is significantly enhanced in hyperbolic media, with the Purcell factor depending on emitter size and remaining finite without losses.

Contribution

It provides a detailed analysis of radiative decay and Purcell effect in hyperbolic media, highlighting the finite Purcell enhancement even in lossless conditions.

Findings

Radiative decay rate is strongly enhanced in hyperbolic media.

Purcell factor remains finite without losses.

Enhancement depends on emitter size.

Abstract

We study the radiative decay rate and Purcell effect for a finite-size dipole emitter placed in a homogeneous uniaxial medium. We demonstrate that the radiative rate is strongly enhanced when the signs of the longitudinal and transverse dielectric constants of the medium are opposite, and the isofrequency contour has a hyperbolic shape. We reveal that the Purcell enhancement factor remains finite even in the absence of losses, and it depends on the emitter size.