Direct observation of photonic Landau levels and helical edge states in strained honeycomb lattices

O. Jamadi; E. Rozas; G. Salerno; M. Milićević; T. Ozawa; I. Sagnes; A. Lemaître; L. Le Gratiet; A. Harouri; I. Carusotto; J. Bloch; A. Amo

doi:10.1038/s41377-020-00377-6

arXiv · 2001.10395

Direct observation of photonic Landau levels and helical edge states in strained honeycomb lattices

O. Jamadi·E. Rozas·G. Salerno·M. Milićević·T. Ozawa·I. Sagnes·A. Lemaître·L. Le Gratiet·A. Harouri·I. Carusotto·J. Bloch·A. Amo

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Abstract

We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars. A strong synthetic field is induced in both the s and p orbital bands by engineering a uniaxial hopping gradient in the lattice, giving rise to the formation of Landau levels at the Dirac points. We provide direct evidence of the sublattice symmetry breaking of the lowest-order Landau level wavefunction, a distinctive feature of synthetic magnetic fields. Our realization implements helical edge states in the gap between n=0 and n=1 Landau levels, experimentally demonstrating a novel way of engineering propagating edge states in photonic lattices. In light of recent advances in the enhancement of polariton-polariton nonlinearities, the Landau levels reported here are promising for the study of the interplay between pseudomagnetism and interactions in a photonic system.

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O. Jamadi, E. Rozas, G. Salerno, M. Milićević, T. Ozawa, I. Sagnes, A. Lemaître, L. Le Gratiet, A. Harouri, I. Carusotto, J. Bloch, A. Amo. 2021-01-05. Direct observation of photonic Landau levels and helical edge states in strained honeycomb lattices. https://doi.org/10.1038/s41377-020-00377-6

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