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Observation of a Charge-2 Photonic Weyl Point in the Infrared

: Vaidya, Sachin; Noh, Jiho; Cerjan, Alexander; Jörg, Christina; Freymann, G. von; Rechtsman, Mikael C.


Physical review letters 125 (2020), Nr.25, Art. 253902
ISSN: 0031-9007
ISSN: 1079-7114
Fraunhofer ITWM ()

Weyl points are robust point degeneracies in the band structure of a periodic material, which act as monopoles of Berry curvature. They have been at the forefront of research in three-dimensional topological materials as they are associated with novel behavior both in the bulk and on the surface. Here, we present the experimental observation of a charge-2 photonic Weyl point in a low-index-contrast photonic crystal fabricated by two-photon polymerization. The reflection spectrum obtained via Fourier-transform infrared spectroscopy closely matches simulations and shows two bands with quadratic dispersion around a point degeneracy.