Tailoring topological transition of anisotropic polaritons by interface engineering in biaxial crystals

Abstract

Polaritons in polar biaxial crystals with extreme anisotropy offer a promising route to manipulate nanoscale light-matter interactions. The dynamical modulation of their dispersion is great significance for future integrated nano-optics but remains challenging. Here, we report a momentum-directed strategy, a coupling between the modes with extra momentum supported by the interface and in-plane hyperbolic polaritons, to tailor topological transitions of anisotropic polaritons in biaxial crystals. We experimentally demonstrate such tailored polaritons at the interface of heterostructures between graphene and α-phase molybdenum trioxide (α-MoO3). The interlayer coupling can be electrically modulated by changing the Fermi level in graphene, enabling a dynamic topological transition. More interestingly, we found that the topological transition occurs at a constant Fermi level when tuning the thickness of α-MoO3. The momentum-directed strategy implemented by interface engineering offers new insights for optical topological transitions, which may shed new light for programmable polaritonics, energy transfer and neuromorphic photonics.

References in corpus (8)

• Strong light-matter coupling in two-dimensional atomic crystals
• Sub-diffractional, volume-confined polaritons in a natural hyperbolic material: hexagonal boron nitride
• Observation of topological polaritons and photonic magic angles in twisted van der Waals bi-layers
• Plasmons and screening in monolayer and multilayer black phosphorus
• Infrared hyperbolic metasurface based on nanostructured van der Waals materials
• Configure polaritons in twisted $\alpha$-MoO3
• Femtosecond photo-switching of interface polaritons in black phosphorus heterostructures
• Active tuning of highly anisotropic phonon polaritons in van der Waals crystal slabs by gated graphene

Cited by in corpus (8)

• Gate-tunable negative refraction of mid-infrared polaritons
• Doping-driven topological polaritons in graphene/α-MoO3 heterostructures
• Multiple and spectrally robust photonic magic angles in reconfigurable α-MoO3 trilayers
• Tunable optical topological transitions of plasmon polaritons in WTe2 van der Waals films
• Twist-angle and thickness-ratio tuning of plasmon polaritons in twisted bilayer van der Waals films
• Charge-Transfer Hyperbolic Polaritons in $\alpha$-MoO${}_3$/graphene heterostructures
• Guiding light with surface exciton-polaritons in atomically thin superlattices
• Anisotropic exciton-polaritons reveal non-Hermitian topology in van der Waals materials