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arXiv · 2404.12714

Lasing and spasing with active individual core-shell plasmonic nanoresonators

Dávid Vass·András Szenes·Péter Zoltán Nagy·Balázs Bánhelyi·Mária Csete
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Abstract

Active core-shell nanoresonators were designed in order to achieve large near-field enhancement, large power-outflow and minimal spaser threshold in the pump E-field strength. Gain-metal-dielectric (GMD) and gain-metal-gain (GMG) nanoresonator compositions were optimized with corresponding objective functions. The average local E-field, power-outflow and extinction cross-section were mapped above the pump E-field strength and dye concentration parameter plane with the criterion that the local E-field is smaller than the damage threshold of the nanoresonator. Regions, corresponding to the maxima in the average local E-field, the highest power-outflow, or to the zero-crossing of the extinction cross-section, were selected for detailed studies. The spectral distribution of the near-field enhancement, optical cross-sections, optical responses, quantum efficiencies, as well as the polar angle distribution of the far-field radiated power and the local charge distribution of dominant modes were inspected. Based on the results the GMD nanoresonator composition is proposed to maximize local E-field in near-field amplifiers, to maximize power-outflow in far-field-emitting lasers and to minimize threshold E-field in spasers. Comparing the complete characteristics, both compositions are suitable for different operation regions, the GMG is proposed as near-field amplifier and far-field out-coupling nanolaser, whereas the GMD is unambiguously preferable to achieve optimal spaser properties.

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Dávid Vass, András Szenes, Péter Zoltán Nagy, Balázs Bánhelyi, Mária Csete. 2024-04-19. Lasing and spasing with active individual core-shell plasmonic nanoresonators. https://arxiv.org/abs/2404.12714

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