arXiv2026
The discovery of in-plane anisotropic excitons in van der Waals semiconductors enables state-of-the-art nanophotonic applications. A key parameter of these quasiparticles is the coherence time (T2), which measures quantum dephasing and determines how long coherent superpositions can be preserved - critical for quantum photonic and excitonic technologies. In particular, such systems pose fundamental questions about how anisotropy influences coherence properties. Here, we employ transient micro-four-wave mixing spectroscopy to study the coherence and population dynamics (T_1) of excitons at resonance in pristine layered rhenium disulfide. We probe and quantify the dephasing induced by many-body excitonic scattering processes, revealing signatures of anisotropy and one-dimensional features. This results in notable decoherence resilience against variations in optical excitation density and temperature, enabling measurables quantum features even at room temperature. Additionally, the absence of photon echo signals highlights the homogeneous nature of excitonic transitions in ReS2 and reflects a low level of disorder across few-layer to bulk-like flakes. These findings open further exploration of in-plane anisotropy-driven decoherence in van der Waals materials, while creating valuable possibilities for quantum-based applications.