Szenes András, Bánhelyi Balázs, Szabó Lóránt Zs, Szabó Gábor, Csendes Tibor, Csete Mária
Department of Optics and Quantum Electronics, University of Szeged, Dóm tér 9 Szeged, H-6720, Hungary.
Institute of Informatics, University of Szeged, Árpád tér 2, Szeged, H-6720, Hungary.
Sci Rep. 2017 Oct 23;7(1):13845. doi: 10.1038/s41598-017-14227-w.
Configuration of three different concave silver core-shell nanoresonators was numerically optimized to enhance the excitation and emission of embedded silicon vacancy (SiV) diamond color centers simultaneously. Conditional optimization was performed to ensure ~20-30-40 and 50% apparent quantum efficiency (cQE) of SiV color centers. The enhancement spectra, as well as the near-field and charge distribution were inspected to uncover the underlying nanophotonical phenomena. The conditionally optimized coupled systems were qualified by the product of the radiative rate enhancements at the excitation and emission, which is nominated as P factor. The optimized spherical core-shell nanoresonator containing a centralized emitter is capable of enhancing the emission considerably via bonding dipolar resonance. The P factor is 529-fold with 49.7% cQE at the emission. Decentralization of the emitter leads to appearance of higher order nonradiative multipolar modes. Transversal and longitudinal dipolar resonance of the optimized ellipsoidal core-shell resonator was tuned to the excitation and emission, which results in 6.2∙10 P factor with 50.6% cQE at the emission. Rod-shaped concave core-shell nanoresonators exploit similar transversal and longitudinal dipolar resonance, moreover they enhance the fluorescence more significantly due to their antenna-like geometry. P factor indicating 8.34∙10 enhancement is achievable while the cQE is 50.3% at the emission.
对三种不同的凹面银核壳纳米谐振器进行了数值优化，以同时增强嵌入式硅空位（SiV）金刚石色心的激发和发射。进行了条件优化，以确保SiV色心的表观量子效率（cQE）达到约20%、30%、40%和50%。检查了增强光谱以及近场和电荷分布，以揭示潜在的纳米光子现象。通过激发和发射时辐射率增强的乘积对条件优化的耦合系统进行评估，该乘积被命名为P因子。优化后的包含集中发射器的球形核壳纳米谐振器能够通过键合偶极共振显著增强发射。发射时P因子为529倍，cQE为49.7%。发射器的分散导致出现高阶非辐射多极模式。将优化后的椭球形核壳谐振器的横向和纵向偶极共振调谐到激发和发射，发射时产生6.2×10的P因子，cQE为50.6%。棒状凹面核壳纳米谐振器利用类似的横向和纵向偶极共振，此外，由于其天线状几何结构，它们能更显著地增强荧光。发射时cQE为50.3%，可实现8.34×10的P因子增强。
