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arXiv · 2406.05214

Topologically tunable polaritons based on two-dimensional crystals in a photonic lattice

Lukas Lackner·Oleg A. Egorov·Anthony Ernzerhof·Christoph Bennenhei·Victor N. Mitryakhin·Gilbert Leibeling·Falk Eilenberger·Seth Ariel Tongay·Ulf Peschel·Martin Esmann·Christian Schneider
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Abstract

Topological photonics is an emergent research discipline which interlinks fundamental aspects of photonics, information processing and solid-state physics. Exciton-polaritons are a specifically interesting platform to study topological phenomena, since the coherent light matter coupling enables new degrees of freedom such as tunable non-linearities, chiralities and dissipation. Room-temperature operation of such exciton-polaritons relies on materials comprising both, large exciton binding energies and oscillator strength. We harness widely spectrally tunable, room temperature exciton-polaritons based on a WS2 monolayer in an open optical cavity to realize a polariton potential landscape which emulates the Su-Schrieffer-Heeger (SSH) Hamiltonian. It comprises a domain boundary hosting a topological, exponentially localized mode at the interface between two lattices characterized by different Zak-phases which features a spectral tunability over a range as large as 80 meV. Moreover, we utilize the unique tilt-tunability of our implementation, to transform the SSH-lattice into a Stark-ladder. This transformation couples the topologically protected defect mode to propagating lattice modes, and effectively changes the symmetry of the system. Furthermore, it allows us to directly quantify the Zak-phase difference $\Delta_{Zak}=(1.13\pm 0.11)\pi$ between the two topological phases. Our work comprises an important step towards in-situ tuning topological lattices to control and guide light on non-linear chips.

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Lukas Lackner, Oleg A. Egorov, Anthony Ernzerhof, Christoph Bennenhei, Victor N. Mitryakhin, Gilbert Leibeling, Falk Eilenberger, Seth Ariel Tongay, Ulf Peschel, Martin Esmann, Christian Schneider. 2024-06-07. Topologically tunable polaritons based on two-dimensional crystals in a photonic lattice. https://doi.org/10.1103/qphl-qd37

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