Chiral nonlinear polaritonics with van der Waals metasurfaces
- Connor Heimig
- Alexander A. Antonov
- Dmytro Gryb
- Thomas Possmayer
- Thomas Weber
- Michael Hirler
- Jonas Biechteler
- Luca Sortino
- Leonardo de S. Menezes
- Stefan A. Maier
- Maxim V. Gorkunov
- Yuri Kivshar
- Andreas Tittl
2026-03-27
Chiral optical cavities are crucial for the development of nonequilibrium quantum materials by discriminating and selectively coupling to light of a specific circular polarization, but fundamentally cannot be realized with conventional mirror cavities. Here, we demonstrate this unique functionality by developing a monolithic transition metal dichalcogenide (TMDC) metasurface with broken out-of-plane symmetry, allowing for the selective formation of self-hybridized chiral exciton-polaritons. Our metasurface maintains maximal chirality for oblique incidence up to 20°, thereby outperforming all previously known designs. Moreover, we study the chiral strong-coupling regime in nonlinear experiments and reveal polaritonic signatures in chiral third-harmonic generation. Our results position maximally chiral van der Waals (vdW) metasurfaces as a versatile platform for tunable chiral polaritonics with applications in nonreciprocal photonic devices and valleytronics.