Project period: 2026-2028
Polaritons, the quasiparticles of light—matter interactions, are promising building blocks for emerging technologies that bridge solid-state quantum systems with nanophotonics. This project is devoted to a little-explored form of light—matter interactions, the Mie excitons that result from strong coupling of Mie modes in high-index dielectric nanoparticles (e.g. silicon) with collective excitonic states in two-dimensional semiconductors (e.g. tungsten disulfide). Such polaritons emerged recently as low-loss versatile systems with both electric and magnetic character, but are still hard to excite and detect in practice. Combining analytics, computational electrodynamics and experiments, the project uses electron beams in a scanning electron microscope to measure cathodoluminescence spectra and quantify the radiation emitted by the hybrid system, allowing a more efficient coupling and shedding light on the physics governing a promising alternative to nanophotonic polaritonic templates based on plasmons.
More information about the project
The project is organised in two scientific tasks:
1) Theoretical development: While the fully electrodynamic description of nanoparticles interacting with electrons with aloof trajectories was developed already in the late 1990s, only recently was the corresponding solution for penetrating electrons developed at POLIMA, still restricted to free-standing spherical nanoparticles. Extension to substrate-supported particles is critical to this project, and it is being developed by combining appropriate electromagnetic-field expansions in each region, thus mixing the Mie and transfer-matrix methods. The developed treatment is further combined with the extended-boundary condition method to allow considering different shapes of nanoparticles.
2) Experimental realisation: Experiments with two-dimensional transition-metal dichalcogenides combined with dielectric nanoparticles of different shapes are conducted at the POLIMA cathodoluminescence lab. Transition-metal dichalcogenide films of different thicknesses, ranging from single monolayers to “bulk” are exfoliated, and silicon particles are deposited on them, with cathodoluminescence spectra being collected for different impact parameters and velocities.
Christos Tserkezis
The project is supported by the Independent Research Fund Denmark (Grant No. 5281-00155B) and Danish National Research Foundation (Project No. DNRF165, POLIMA)
