Material properties in the strong light-matter coupling regime

An electromagnetic mode without photonic excitations still has a non-zero energy - called zero-point energy. The resulting vacuum fluctuations give rise to long known physical effects such as the spontaneous emission.

By engineering electromagnetic modes in cavities, vacuum can be made to interact with matter in the extensively studied weak, strong and ultrastrong light-matter coupling regimes.

The term `light-matter coupling', as well as the optical experimental means by which the regime is usually studied, hides this important fact: vacuum alone gives rise to the coupling and to the mixed light-matter excitations (polaritons) of the system.In physics, still only few experimental platforms have allowed to observe `vacuum-matter coupling' without photonic excitations.

Properties of materials dressed by a cavity were successfully observed by measuring their conductivity [Orgiu et al. Nat. Mater. 14, 1123 (2015); Paravicini-B. et al. Nat. Phys. 15, 186 (2019)].

In recent years, the new field of polaritonic chemistry has identified other material properties altered by vacuum coupling, including chemical reaction rates and thermodynamic properties.In this project, we intend to expand the new experimental access to the matter part via conductivity measurements to an entirely new system.

So far, only highly disordered organic semiconductors [Orgiu] and very high mobility GaAs based electron gases were used [Paravicini-B.]. Here, we suggest a new platform using transition metal dichalcogenides inside a plasmonic cavity.

This should work at room temperature and shed more light on the mechanism responsible for vacuum field assisted charge transport. In a second project, we attempt to alter phase transition properties by dressing a chemical to a cavity. Both projects aim to explore the potential of engineering properties of materials with a cavities vacuum field mode.

They both mostly rely on optical, electronic and chemical experimental tools available in the host group.