for an incident TM polarized excitation at $1.96$ eV. Fig. \[fig:4\](e) displays the same coefficient under TE excitation. A clear polarization anisotropy on the chiraliton emission is observed for both TM and TE excitation polarizations, both featuring the same symmetry along the $k_x=0$ axis as the differential reflectivity dispersion map $R_{\textrm{\tiny TM}}-R_{\textrm{\tiny TE}}$ shown in Fig. \[fig:4\](d). As detailed in the Supporting Information (Sec. F), the degree of chiralitonic intervalley coherence can be directly quantified by the difference $(S_1^{\textrm{\tiny out}}|_{\textrm{\tiny
    TM}}-S_1^{\textrm{\tiny out}}|_{\textrm{\tiny TE}})/2$, which measures the PL linear depolarization factor displayed (as $m_{11}$) in Fig. \[fig:4\] (f). By this procedure, we retrieve a chiralitonic intervalley coherence that varies between $5\%$ and $8\%$ depending on $k_x$. Interestingly, these values that we reach at RT have magnitudes comparable to those reported on a bare WS$_2$ monolayer at 10 K [@Xiaodong2014]. This unambiguously shows how such strongly coupled TMD systems can sustain RT coherent dynamics robust enough to be observed despite the long exciton PL lifetimes and plasmonic propagation distances.

In summary, we demonstrate valley contrasting spin-momentum locked chiralitonic states in an atomically thin TMD semiconductor strongly coupled to a plasmonic OSO resonator. Likely, the observation of such contrasts even after 200 ps 