lifetimes is made possible by the unexpectedly robust RT coherences inherent to the strong coupling regime. Exploiting such robust coherences, we measure chiralitonic flows that can evolve in superpositions over micron scale distances. Our results show that the combination of OSO interactions with TMD valleytronics is an interesting path to follow in order to explore and manipulate RT coherences in chiral quantum architectures [@Coles2016; @low2016polaritons].

We thank David Hagenmüller for fruitful discussions. This work was supported in part by the ANR Equipex “Union” (ANR-10-EQPX-52-01), ANR Grant (H2DH ANR-15-CE24-0016), the Labex NIE projects (ANR-11-LABX-0058-NIE) and USIAS within the Investissement d’Avenir program ANR-10-IDEX-0002-02. Y. G. acknowledges support from the Ministry of Science, Technology and Space, Israel. S. B. is a member of the Institut Universitaire de France (IUF).

[*Author Contributions -*]{} T. C. and S. A. contributed equally to this work.

Supporting Information
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A: Linear absorption dispersion analysis
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Angle resolved absorption spectra are given from the measured reflectivity of the WS$_2$ flake on top of the plasmonic grating $R_{\tiny\textrm{sample}}$ with: $$A = 1 - R_{\tiny\textrm{sample}}/R_{\tiny\textrm{substrate}},$$ where $R_{\tiny\textrm{substrate}}$ is the angle resolved reflectivity of the optically thick (200 nm thickness) Au substrate. The $1\%$ max. transmission through the structure can be 