DETERMINISTIC NANOANTENNA-ENHANCED SINGLE-PHOTON EMISSION FROM WSE₂ FOR QUANTUM COMMUNICATION NETWORKS

Quantum technologies demand scalable, deterministic single-photon sources with high brightness, purity, and indistinguishability. Here, we introduce a hybrid platform integrating strain-engineered quantum emitters in tungsten diselenide (WSe₂) monolayers with dielectric bullseye nanoantennas. Finite-difference time-domain simulations optimized the grating (10 rings, 200 nm period) for Purcell enhancement Fp ≈ 110 at 740 nm, collection efficiency η = 75% into low-NA modes, and directivity D ≈ 25 dB, with electromagnetic hotspots boosting local density of states 5× while preserving g² (0) < 0.05 antibunching. Experimental validation across 120 cryogenic devices confirmed Fp = 25 ± 2 and η = 78 ± 4%, yielding 8× brightness (400 kcps) and 26× efficiency gains over bare emitters, surpassing nitrogen-vacancy centers and quantum dot cavities. Nanopillar arrays (500 nm pitch) induced tensile strain (ε ≈ 0.8 × 10-3) for 92% emitter yield with 12.8 nm (90th percentile) alignment precision, enabling >90% grating overlap. Spectral linewidths narrowed to Δλ = 1.5 ± 0.3 nm, lifetimes to τ_rad = 0.20 ns, and second-order correlations to g² (0) = 0.06 ± 0.01, with coherence T₂* = 1.5 ns. Hong-Ou-Mandel interferometry demonstrated photon indistinguishability V = 0.85 ± 0.03, exceeding protocol thresholds (V > 0.7) via stable central wavelengths (0.21 pm rms) and transform-limited linewidths Γ = 4.7 pm. 1/f noise dominated fluctuations, but end-to-end η > 65% projects >1 photon/pulse at MHz rates. This all-dielectric, planar approach evades plasmonic losses (β > 0.9), supports valleytronic encoding, and scales to arrays for fault-tolerant networks, bridging 2D materials to photonic integration.