Abstract
We consider light scattering by two-dimensional arrays of high-index dielectric spheres arranged into a triangular lattice. It is demonstrated that in the case of a triple degeneracy of resonant leaky modes in the gamma point, the scattering spectra exhibit a complicated picture of Fano resonances with extremely narrow linewidth. The Fano features are explained through coupled-mode theory for a Dirac cone spectrum as a signature of optical bound states in the continuum (BIC). It is found that the standing wave in-gamma BIC induces a ring of off-gamma BICs due to different scaling laws for real and imaginary parts of the resonant eigenfrequencies in the Dirac cone spectrum. A quantitative theory of the spectra is proposed.
© 2019 Optical Society of America
Full Article | PDF ArticleMore Like This
E. N. Bulgakov and D. N. Maksimov
J. Opt. Soc. Am. B 35(10) 2443-2452 (2018)
G. Y. Chen, W. X. Zhang, and X. D. Zhang
Opt. Express 27(12) 16449-16460 (2019)
Sun-Goo Lee, Seong-Han Kim, and Chul-Sik Kee
Opt. Express 29(14) 21492-21501 (2021)