Electromagnetic Field Enhancement in Bloch Surface Waves

TL;DR

This paper compares guided modes in slab waveguides and Bloch Surface Waves (BSWs), showing that BSWs can often provide superior electromagnetic field enhancement and energy density for light-matter interaction applications.

Contribution

It provides a systematic, wavelength-independent comparison demonstrating that BSWs can outperform slab waveguide modes in electromagnetic field enhancement.

Findings

Best surface field enhancement in slab waveguides is comparable to BSWs.

BSWs are often preferable for maximizing local electromagnetic energy density.

Results are applicable across a wide range of refractive indices.

Abstract

We present a systematic comparison between guided modes supported by slab waveguides and Bloch Surface Waves (BSWs) propagating at the surface of truncated periodic multilayers. We show that, contrary to common belief, the best surface field enhancement achievable for guided modes in a slab waveguide is comparable to that observed for BSWs. At the same time, we demonstrate that, if one is interested in maximizing the electromagnetic energy density at a generic point of a dielectric planar structure, BSWs are often preferable to modes in which light is confined uniquely by total internal reflection. Since these results are wavelength independent and have been obtained by considering a very wide range of refractive indices of the structure constituent materials, we believe they can prove helpful in the design of future structures for the control and the enhancement of the light-matter interaction.