Photonic energy band structure of excitonic quantum dot dimer system
2009 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, no 5Article in journal (Refereed) Published
We study the energy dispersion of a photonic crystal composed of two types of excitonic quantum dots (QD dimer system), type-I QDs at their ground states while type-II QDs are already excited. The excitation and de-excitation of the exciton states in the QDs by an external electromagnetic field contribute extra dielectric polarizations with respect to the background material, thus a contrast in the dielectric constant and the eventual formation of the photonic dispersion. By assuming periodic boundary conditions, it has been shown that the photonic dispersion of the QD dimer system is composed of modified but still characteristic dispersions of the two types of QDs in their separate photonic crystal formats. Starting from the transparent condition of type-II QDs, the photonic structure of the QD dimer system evolves from the one of type-I QDs to the composite dimer system. The modification due to the radiative interaction between the two types of the QDs is symmetric with respect to the change in the excitation degree of type-II QDs (increase/decrease the excitation degree from transparent status so that type-II QDs become optically gain/lossy). It is thus concluded that the transport of an external electromagnetic field is normal in the QD dimer system and achieving a lossless negative-dielectric material at a single frequency is possible by using the QD dimer system.
Place, publisher, year, edition, pages
2009. Vol. 106, no 5
band structure, composite materials, dielectric materials, dielectric, polarisation, excited states, excitons, ground states, permittivity, photonic band gap, photonic crystals, quantum dots, electromagnetic-waves, crystal, polaritons, lattices, fabrication, metal
IdentifiersURN: urn:nbn:se:kth:diva-18768DOI: 10.1063/1.3211322ISI: 000269850300100ScopusID: 2-s2.0-70349304318OAI: oai:DiVA.org:kth-18768DiVA: diva2:336815
QC 201005252010-08-052010-08-052010-12-22Bibliographically approved