Dielectric nanoantennas for surface-enhanced fluorescence spectroscopy and efficient harmonic generation

Dielectric nanoantennas have recently emerged as promising alternative candidates to plasmonic systems in the visible range.1,2 When excited above their bandgap energies, high-refractive-index dielectric nanostructures can... [ view full abstract ]

Dielectric nanoantennas have recently emerged as promising alternative candidates to plasmonic systems in the visible range.^1,2 When excited above their bandgap energies, high-refractive-index dielectric nanostructures can highly concentrate electric and magnetic fields within subwavelength volumes while presenting ultra-low absorption compared to metals.³ In particular, by locally enhancing the incident light intensity, dielectric nanoantennas are expected not only to produce negligible heating, but also boost nonlinear phenomena and surface-enhanced spectroscopies, since their efficiencies increase with the excitation density.

In this presentation, GaP and Ge nanoantennas will be introduced as promising nanosystems for surface-enhanced fluorescence and second and third harmonic generation on the nanoscale at visible wavelengths.^3-5 Fluorescence enhancement factors of over 3000 and harmonic conversion efficiencies of 10^-3% will be demonstrated for suitably engineered dielectric nanostructures. Finally, hybrid dielectric/metallic Si/Au nanoantennas will also be analyzed.⁶

¹Albella, P.; Poyli, M. A.; Schmidt, M. K.; Maier, S. A.; Moreno, F.; Sáenz, J. J.; Aizpurua, J. J. Phys. Chem. C 2013, 117, 13573-13584.

² Shorokhov, A. S.; Melik-Gaykazyan, E. V.; Smirnova, D. A.; Hopkins, B.; Chong, K. E.; Choi, D. Y.; Shcherbakov, M. R.; Miroshnichenko, A. E.; Neshev, D. N.; Fedyanin, A. A.; Kivshar, Y. S. Nano Lett. 2016, 16, 4857–4861.

³ Grinblat, G.; Li, Y.; Nielsen, M., Oulton R. F.; Maier S. A. Nano Lett. 2016, 16, 4635-4640.

⁴ Grinblat, G.; Li, Y.; Nielsen, M., Oulton R. F.; Maier S. A. ACS Nano 2017, 11, 953–960.

⁵ Cambiasso, J.; Grinblat, G.; Li, Yi.; Rakovich, A.; Cortés, E.; Maier, S. A. Nano Lett. 2017, 17, 1219–1225.

⁶ Shibanuma, T.; Grinblat, G.; Albella, P.; Maier S. A. Nano Lett. 2017, DOI: 10.1021/acs.nanolett.7b00462.