Photonic band gaps and defect states induced by excitations of Bose-Einstein condensates in optical lattices

TL;DR

This paper investigates how Bose-Einstein condensates in optical lattices influence photonic band gaps and defect states, revealing how excitations create localized defect states within the band gaps.

Contribution

It introduces a model for the interaction between condensate excitations and photonic band structures, highlighting the formation of defect states due to elementary excitations.

Findings

Condensates create photonic band gaps at optical frequencies.

Elementary excitations induce defect states within the band gaps.

Localized defect states' frequencies are calculated using the Koster-Slater model.

Abstract

We study the interaction of a Bose-Einstein condensate, which is confined in an optical lattice, with a largely detuned light field propagating through the condensate. If the condensate is in its ground state it acts as a periodic dielectric and gives rise to photonic band gaps at optical frequencies. The band structure of the combined system of condensed lattice-atoms and photons is studied by using the concept of polaritons. If elementary excitations of the condensate are present, they will produce defect states inside the photonic band gaps. The frequency of localized defect states is calculated using the Koster-Slater model.