Investigations of Strong Light-Matter Interactions in Nanophotonic Systems
Doctoral thesis, 2019
When the light-matter interaction becomes strong enough, the system enters a special regime, so-called strong coupling. In this regime, the cavity and emitter exchange their energy in a coherent manner on time scales that are faster than their respective dissipation rates. This leads to the formation of new hybrid light-matter states, referred to as polaritons. In this strong light-matter coupling regime, not only the optical but also material-related properties of the system can be modified.
The aim of this thesis is to show and discuss room temperature strong light-matter coupling as well as beneficial and limiting factors of the coupling process. Excitons in transition metal dichalcogenides (TMDC) are coupled to plasmonic resonances of individual gold nanobipyramids (BPs). Strong coupling of excitons and BPs in a single hot-spot is demonstrated. Subsequentially, the asymmetric photoluminescence (PL) emission behavior of this hybrid system is investigated and discussed. Moreover, an interesting case of strong coupling arises when the TMDC material itself is made thick enough to support resonant Fabry-Pérot optical modes in the same frequency range as the exciton resonance. In such circumstances the excitons can be self-hybridized with the optical resonator made of the same material and thereby modify the absorption of the TMDC material over the whole visible spectrum.
In addition to the above-mentioned studies of strong coupling, nonlinear laser microscopy has been employed to study plasmonic, as well as biological samples. And finally, the effect of temporal PL coherence from a single plasmonic nanoparticle is demonstrated as well as different methods for sample analysis and understanding their limitations are discussed.
localized surface plasmon resonance
Chalmers, Physics, Bionanophotonics
Phase control of plasmon enhanced two-photon photoluminescence in resonant gold nanoantennas
Applied Physics Letters,; Vol. 113(2018)
Strong Light-Matter Coupling between Plasmons in Individual Gold Bi-pyramids and Excitons in Mono- and Multilayer WSe2
Nano Letters,; Vol. 18(2018)p. 5938-5945
Self-Hybridized Exciton-Polaritons in Multilayers of Transition Metal Dichalcogenides for Efficient Light Absorption
ACS Photonics,; Vol. 6(2019)p. 139-147
In modern science, strong light-matter interactions or strong coupling, is very attractive due to its ability to merge different fields of physics, namely quantum optics and material science. Furthermore, many interesting effects in quantum physics require cooling to temperatures below -200 degree Celsius, whereas strong coupling could make them accessible at ambient conditions.
This thesis aims to contribute in a better understanding of single plasmonic nanoparticle strong coupling with excitonic materials at ambient conditions.
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4613
Chalmers University of Technology
PJ lecture hall
Opponent: Nicolas Stenger, DTU Fotonik, Denmark