title: Broadband asymmetric light transmission through tapered metallic gratings at visible frequencies.
abstract: Asymmetric transmission phenomenon has attracted tremendous research interest due to its potential applications in integrated photonic systems. Broadband asymmetric transmission (BAT) is a highly desirable but challenging functionality to achieve in the visible regime due to the limitation of material dispersion. In this paper, we propose and numerically demonstrate that a tapered-metal-grating structure (TMGS) can achieve high-contrast BAT spectra covering the entire visible region. The transmission efficiency reaches ~95% for the forward illumination and ~35% for the backward illumination at the same wavelengths, respectively, and the corresponding transmission ratio is larger than 2.5 over a broadband wavelength regime. Such a design with high performance suggests applications for unidirectional optical transmission, optical diode, and so on.
authors.affiliation: School of Mathematics &Physics, Changzhou University, Changzhou 213164, China.|Department of Electrical Engineering and Computer Science, Northwestern University, IL 60208, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Tang
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, IL 60208, USA.
authors.forename: Zhongyang
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, IL 60208, USA.
authors.forename: Zizhuo
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, IL 60208, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Callewaert
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, IL 60208, USA.
authors.forename: Koray
authors.initials: K
authors.lastname: Aydin