New material layer selects light by spin, opening door to optical devices
Researchers created a ultrathin metasurface that picks out light spinning in one direction while rejecting the opposite—a capability that's been theoretically impossible until now. The advance could enable new types of photonic devices and quantum computing components, with potential applications in telecommunications and sensing technology.
Originaltitel: Chiral nonlinear polaritonics with van der Waals metasurfaces
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.