Dresden 2026 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 54: 2D Materials IX – Photonic properties and devices

HL 54.5: Vortrag

Freitag, 13. März 2026, 10:30–10:45, POT/0081

quantum electrodynamics of excitons in bilayer graphene — •abraham nava mireles — the institut of photonic sciences, castelldefels, spain.

Cavity quantum electrodynamics has been a cornerstone in understanding light-matter interactions. In the so-called strong-coupling regime, these interactions cannot be described as a simple combination of their light and matter components. Instead, light and matter form new hybrid states. This project aims to push beyond into the ultrastrong coupling (USC) regime, where the interaction strength becomes comparable to the system's transition frequencies. In this regime, quantum vacuum fluctuations and elementary excitations become significant. This enables not only the control of quantum effects but also the modification of a material's ground state, even in the absence of external light. To that end, we explore the coupling between confined hyperbolic phonon polaritons (HPhPs) in hexagonal boron nitride (hBN) and excitons in bilayer graphene (BLG). The hyperbolic nature enables deep subwavelength confinement, enhancing the photonic density of states. In BLG, extended dipole transitions exhibit a nonlocal optical response, in which propagating HPhPs allow momentum-dependent transitions and access to a continuum of electronic final states. This leads to enhanced emission rates and to each exciton effectively coupling to multiple polaritonic modes, ultimately reaching a regime where the coupling strength compares to the transition frequency. This platform opens new possibilities for quantum technologies and non-perturbative light-matter engineering.

Keywords: cavity QED; ultra strong coupling; excitons; hyperbolic phonon polaritons; bilayer graphene