Vass Dávid, Szenes András, Bánhelyi Balázs, Csete Mária
Department of Optics and Quantum Electronics, University of Szeged, Dóm tér 9, 6720 Szeged, Hungary.
Department of Computational Optimization, University of Szeged, Árpád tér 2, 6720 Szeged, Hungary.
Nanomaterials (Basel). 2022 Jan 22;12(3):352. doi: 10.3390/nano12030352.
Superradiance was demonstrated in broken-symmetry arrays of SiV diamond color centers embedded into concave plasmonic nanoresonators. The coupled configurations, including the diamond-silver (bare) and diamond-silver-diamond (coated) nanoresonators' geometry parameters as well as the emitters' azimuthal orientation and distance from the metal, were numerically optimized. An objective function consisting of the total fluorescence enhancement multiplied by the corrected emission quantum efficiency was used to design nanoresonators that promote superradiance. A larger total fluorescence enhancement was achieved via a larger number of emitters in both geometries, in coated spherical and in bare ellipsoidal nanoresonators. The superradiance performance was better in the case of a smaller number of emitters in bare spherical and coated ellipsoidal nanoresonators and in the case of a larger number of emitters in coated spherical and bare ellipsoidal nanoresonators. Ellipsoidal geometry is advantageous independent of composition and seeding. The configurations optimal for non-cooperative fluorescence enhancement and superradiance are coincidental. A radiative rate enhancement proportional to the number of emitters was found in wide spectral regions; therefore, superradiance implies -fold enhancements coexist at excitation and emission. In ellipsoidal nanoresonators, the better superradiance achieved via a smaller quality-factor is accompanied by larger frequency pulling.
在嵌入凹面等离子体纳米谐振器的SiV金刚石色心的破缺对称阵列中展示了超辐射。对包括金刚石-银（裸）和金刚石-银-金刚石（涂层）纳米谐振器的几何参数以及发射体的方位取向和与金属的距离在内的耦合配置进行了数值优化。使用由总荧光增强乘以校正后的发射量子效率组成的目标函数来设计促进超辐射的纳米谐振器。在涂层球形和裸椭球形纳米谐振器这两种几何结构中，通过更多数量的发射体实现了更大的总荧光增强。在裸球形和涂层椭球形纳米谐振器中发射体数量较少的情况下以及在涂层球形和裸椭球形纳米谐振器中发射体数量较多的情况下，超辐射性能更好。椭球形几何结构无论其组成和晶种如何都是有利的。对于非合作荧光增强和超辐射而言，最优配置是一致的。在宽光谱区域发现辐射率增强与发射体数量成正比；因此，超辐射意味着在激发和发射时 - 倍增强同时存在。在椭球形纳米谐振器中，通过较小的品质因数实现的更好的超辐射伴随着更大的频率牵引。
