Complex modes in an open lossless periodic waveguide

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)5632-5635
Journal / PublicationOptics Letters
Volume45
Issue number20
Online published6 Oct 2020
Publication statusPublished - 15 Oct 2020

Abstract

Guided modes of an open periodic waveguide, with a periodicity in the main propagation direction, are Bloch modes confined around the waveguide core with no radiation loss in the transverse directions. Some guided modes can have a complex propagation constant, i.e., a complex Bloch wavenumber, even when the periodic waveguide is lossless (no absorption loss). These so-called complex modes are physical solutions that can be excited by incident waves whenever the waveguide has discontinuities or defects. We show that the complex modes in an open dielectric periodic waveguide form bands, and the endpoints of the bands can be classified to a small number of cases, including extrema on dispersion curves of the regular guided modes, bound states in the continuum, degenerate complex modes, and special diffraction solutions with blazing properties. Our study provides an improved theoretical understanding of periodic waveguides and a useful guidance to their practical applications.

Citation Format(s)

Complex modes in an open lossless periodic waveguide. / ABDRABOU, Amgad; LU, Ya Yan.
In: Optics Letters, Vol. 45, No. 20, 15.10.2020, p. 5632-5635.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review