Quantum theory of photonic crystal polaritons

TL;DR

This paper develops a comprehensive quantum mechanical model for photonic crystal polaritons, revealing their band structure and strong coupling behavior, and validates it against experimental reflectance spectra.

Contribution

It introduces a full quantum theory of photonic crystal polaritons and demonstrates its accuracy through comparison with scattering matrix measurements.

Findings

Observation of anticrossing behavior indicating strong coupling

Quantitative agreement between quantum theory and experimental spectra

Identification of photonic crystal polaritons as mixed light-matter quasiparticles

Abstract

We formulate a full quantum mechanical theory of the interaction between electromagnetic modes in photonic crystal slabs and quantum well excitons embedded in the photonic structure. We apply the formalism to a high index dielectric layer with a periodic patterning suspended in air. The strong coupling between electromagnetic modes lying above the cladding light line and exciton center of mass eigenfunctions manifests itself with the typical anticrossing behavior. The resulting band dispersion corresponds to the quasi-particles coming from the mixing of electromagnetic and material excitations, which we call photonic crystal polaritons. We compare the results obtained by using the quantum theory to variable angle reflectance spectra coming from a scattering matrix approach, and we find very good quantitative agreement.