Emergence of Propagating Exciton-Polaritons in Hybrid Waveguide-van der Waals Heterostructures

Alina Schubert; Karoline Becker; Andreas Thies; Rico Schwartz; Takashi Taniguchi; Kenji Watanabe; Henije Stolz; Alexander Szameit; Matthias Heinrich; Tobias Korn

arXiv · 2607.29289

Emergence of Propagating Exciton-Polaritons in Hybrid Waveguide-van der Waals Heterostructures

Alina Schubert·Karoline Becker·Andreas Thies·Rico Schwartz·Takashi Taniguchi·Kenji Watanabe·Henije Stolz·Alexander Szameit·Matthias Heinrich·Tobias Korn

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Abstract

Integrating few-layer materials into photonic circuits is a promising concept for novel on-chip photonic applications. We incorporate transition metal dichalcogenides (TMDs) with femtosecond-laser-written surface waveguides, which are embedded in fused silica chips. Our novel low-temperature optical spectroscopy setup enables coupling to the waveguide and simultaneous focus from the top to the TMD layer for a distinct excitation and collection of micro-photoluminescence ($\mu$PL) signals in several measurement geometries. Along these lines, we observe spectral changes of the A exciton for encapsulated TMD monolayers when capturing the $\mu$PL signal propagating through the waveguide. Depending on the thickness of the encapsulation with hexagonal boron nitride (hBN), these changes manifest as energetic redshifts of the A exciton, or even a splitting of the A exciton into two components. We attribute this behavior to strong coupling of the waveguide mode and the exciton in the sample, giving rise to the formation of propagating exciton-polaritons. Our interpretation is supported by calculations for a simplified model of a slab waveguide in the vicinity of an exciton by using the transfer matrix method. Having proven to be a highly adaptable framework for the study of propagating polaritons, our experimental platform likewise holds great promise for harnessing the unique properties of exciton-polaristons in integrated photonic circuits.

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Alina Schubert, Karoline Becker, Andreas Thies, Rico Schwartz, Takashi Taniguchi, Kenji Watanabe, Henije Stolz, Alexander Szameit, Matthias Heinrich, Tobias Korn. 2026-07-31. Emergence of Propagating Exciton-Polaritons in Hybrid Waveguide-van der Waals Heterostructures. https://arxiv.org/abs/2607.29289

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