Prolonged Exciton Dephasing in WSe 2 Quantum Emitters Enabled by Geometric Strain Confinement

Two-dimensional semiconductors have emerged as promising platforms for quantum photonics due to the ability to create spatially deterministic quantum emitters (QE) with large exciton binding energies. Despite these benefits, reaching radiation-limited coherence times or single photon indistinguishability remains challenging. Here we show that the T 2 dephasing time of 0D localized excitons in strain-induced QE in WSe 2 can be significantly prolonged through the utilization of programmable 1D strain-folds. Specifically, we demonstrate two approaches to induce pronounced 1D strain folds, either via hBN capping or by adding bowtie-pillar stressors, which both prolong the QE exciton coherence by up to 7-fold, with an average value of T 2 = 15.3 ps and a best case up to T 2 = 25 ps. Furthermore, the influence of the 1D strain on the 0D exciton wave function is directly evident from the strong aligning of the exciton emission dipole along the 1D strain fold, thereby creating strain-controlled single photon polarization. These findings indicate that extended 1D strain fields modify the exciton confinement landscape in a manner that is consistent with reduced sensitivity to intrinsic decoherence channels. Our approach offers a complementary route for coherence enhancement and could be combined in future work with resonant excitation or cavity-coupling schemes toward reaching the regime of single-photon indistinguishability.