Quantum Light Funneling in Tailored Triangular Plasmonic Nanocavities.

Solid-state quantum emitters (QEs) are central to quantum photonic technologies, but existing plasmonic and dielectric cavities rarely combine nanoscale spatial control, high photon flux, and polarization stability. We present a triangular gap-plasmon cavity integrated with monolayer WSe2 that achieves all three by coupling apex-concentrated strain fields with localized optical confinement, thereby realizing deterministic quantum light funneling to a sub-100 nm region. Finite-element simulations identify an optimal 66 nm geometry with a 20° apex angle, maximizing Purcell enhancement near 750 nm. Gold nanotriangles reproducibly activate three strain-induced QEs; the apex emitter exhibits g2 (0) = 0.054 (0.141 when coupled), a lifetime reduction from 16.8 to 0.248 ns (63-fold on average), and saturation counts up to 126 MHz into the first lens. Base emitters show a lower ∼23-fold enhancement, yielding a tip-to-base ratio of 2.7. Polarization studies across 41 QEs confirm dipole alignment within ±5°. When further combining this triangular platform with resonant excitation and tuning schemes, a scalable route toward indistinguishable single-photon sources on chip could be achieved.