Bound States in the Continuum in Multipolar Lattices | Dr. Andrey Bogdanov

Dr. Andrey Bogdanov
ITMO University

Abstract: We develop a theory of bound states in the continuum (BICs) in multipolar lattices -- periodic arrays of resonant multipoles. We predict that BICs are completely robust to changes in lattice parameters remaining pinned to specific directions in the -space. The lack of radiation for BICs in such structures is protected by the symmetry of multipoles forming the lattice. We also show that some multipolar lattices can host BICs forming a continuous line in the -space and such BICs carry zero topological charge. The developed approach sets a direct fundamental relation between the topological charge of BIC and the asymptotic behavior of the Q-factor in its vicinity.

1) Sadrieva, Z., Frizyuk, K., Petrov, M., Kivshar, Y., & Bogdanov, A. (2019). Multipolar origin of bound states in the continuum. Physical Review B, 100(11), 115303.
https://journals.aps.org/prb/abstract...

2) Gladyshev, S., Shalev, A., Frizyuk, K., Ladutenko, K., & Bogdanov, A. (2022). Bound States in the Continuum in Multipolar Lattices. arXiv preprint arXiv:2202.10392.
https://arxiv.org/pdf/2202.10392.pdf

The Department of Physics and Engineering of ITMO University (Saint Petersburg, Russia) hosts online weekly seminars to discuss recent scientific achievements of researchers from all over the world with a wide audience. The topics include experimental (Optical seminar) and theoretical (Theoretical seminar) aspects of nanophotonics, solid-state physics, material science, as well as design and applications of radiofrequency structures and devices (Microwave seminar).

00:00:00 start
00:00:54 Outline
00:01:42 Concept of bound states in the continuum
00:11:12 Applications of multipolar approach
00:12:38 Brewster's angle
00:14:22 Bound states in the continuum in multipolar lattices
00:40:37 Topological charge of bound states in the continuum
00:45:50 Two-multipole approximation
00:48:00 Conclusion
00:48:30 Discussions

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