RESUMEN
Twisted atomically thin semiconductors are characterized by moiré excitons. Their optical signatures and selection rules are well understood. However, their hybridization with photons in the strong coupling regime for heterostructures integrated in an optical cavity has not been the focus of research yet. Here, we combine an excitonic density matrix formalism with a Hopfield approach to provide microscopic insights into moiré exciton polaritons. In particular, we show that exciton-light coupling, polariton energy, and even the number of polariton branches can be controlled via the twist angle. We find that these new hybrid light-exciton states become delocalized relative to the constituent excitons due to the mixing with light and higher-energy excitons. The system can be interpreted as a natural quantum metamaterial with a periodicity that can be engineered via the twist angle. Our study presents a significant advance in microscopic understanding and control of moiré exciton polaritons in twisted atomically thin semiconductors.
RESUMEN
[This corrects the article DOI: 10.1021/acsomega.7b00726.].
RESUMEN
Herein, we present a fabrication approach that produces homogeneous core-satellite SERS encoded particles with minimal interparticle gaps (<2-3 nm) and maximum particle loading, while positioning the encoding agents at the gaps. Integration of plasmonic building blocks of different sizes, shapes, compositions, surface chemistries or encoding agents is achieved in a modular fashion with minimal modification of the general synthetic protocol. These materials present an outstanding optical performance with homogeneous enhancement factors over 4 orders of magnitude as compared with classical SERS encoded particles, which allows their use as single particle labels.
RESUMEN
We propose a simple way to create tunable plasmonic cavities in the infrared (IR) range using graphene films suspended upon a silicon carbide (SiC) grating and present a numerical investigation, using the finite element method, on the absorption properties and field distributions of such resonant structures. We find at certain frequencies within the SiC reststrahlen band that the structured SiC substrate acts as a perfect reflector, providing a cavity effect by establishing graphene plasmon standing waves. We also provide clear evidence of strong coupling phenomena between the localized surface phonon polariton resonances in the SiC grating with the graphene surface plasmon cavity modes, which is revealed by a Rabi splitting in the absorption spectrum. This paves the way to build simple plasmonic structures, using well-known materials and experimental techniques, that can be used to excite graphene plasmons efficiently, even at normal incidence, as well as explore cavity quantum electrodynamics and potential applications in IR spectroscopy.
