Linear and nonlinear optical responses of plasmonic metasurface with sub-nm gaps текст наукової роботи за медичними технологіями з наукового журналу Збірник праць конференції «International Conference on Advanced Laser Technologies (ALT)».
Текст наукової роботи на тему «Linear and nonlinear optical responses of plasmonic metasurface with sub-nm gaps»
Linear and nonlinear optical responses of plasmonic metasurface with sub-nm gaps
T. Takeuchi1, M. Noda1, K. Yabana1
University of Tsukuba, Center for Computational Sciences, Tsukuba, Japan
A plasmonic metasurface in which metallic nano-objects are periodically placed on a plane has attracted substantial attention in terms of its exotic optical characteristics . Although investigations have been devoted mostly to metasurfaces with wavelength or sub-wavelength gap distances between constituent nano-objects, experimental studies have been reported recently for periodic structures with much smaller gap distances, reaching to sub-nm . In isolated systems with a sub-nm gap such as a metallic nanodimer, it has been revealed that optical properties show substantial differences between theoretical descriptions using classical and quantum theories in the linear response regime . The difference becomes remarkable for gap distances less than 0.4 nm  where the quantum tunneling across the gap becomes sizable. Furthermore, very recently, nonlinear responses of plasmonic metasurfaces with sub-nm gaps have been attracting attention since large third-order nonlinear susceptibility has been observed .
We theoretically and numerically investigate the plasmonic metasurface with sub-nm gaps in both linear and nonlinear response regimes. To take into account quantum mechanical effects in the analysis, we employ time-dependent density functional theory (TDDFT) treating the constituent nano-particles by a jellium model. SALMON (https://salmon-tddft.jp/) developed by our group  has been used for the numerical calculation. We will show transmission, reflection, and absorption rates of the metasurface for a weak incident field to elucidate the electron transport effect through the sub-nm gaps. We also show third-order harmonic generations to explore effects of the electron transport on their nonlinear optical response.
 N. Meinzer, W. L. Barnes, and I. R. Hooper, Nat. Photonics 8, 889 (2014 року).
 D. Doyle, N. Charipar, C. Argyropoulos, S. A. Trammell, R. Nita, J. Naciri, A. Pique, J. B. Herzog, and J. Fontana, ACS Photonics 5, 1012 (2017).
 W. Zhu, R. Esteban, A. G. Borisov, J. J. Baumberg, P. Nordlander, H. J. Lezec1, J. Aizpurua, and K. B. Crozier, Nat. Commun. 7, 11495 (2016).
 K. J. Savage, M. M. Hawkeye, R. Esteban, A. G. Borisov, J. Aizpurua, and J. J. Baumberg, Nature 491, 574 (2012).
 L. S. Menezes, L. H. Acioli, M. Maldonado, J. Naciri, N. Charipar, J. Fontana, D. Rativa, C. B. Araujo, and A. S. L. Gomes, J. Opt. Soc. Am. B 36, 1485 (2019).
 M. Noda, SA Sato, Y. Hirokawa, M. Uemoto, T. Takeuchi, S. Yamada, A. Yamada, Y. Shinohara, M. Yamaguchi, K. Iida, I. Floss, T. Otobe, K.-M. Lee, K. Ishimura, T. Boku, G. F. Bertsch, K. Nobusada, K. Yabana, Comput. Phys. Comm 235, 356 (2019).
Завантажити оригінал статті: