Theoretical seminar | 18 May 2022

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.

Main paper/arXiv, related to the seminar, and other references

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/10.1103/PhysRevB.100.115303

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