Eur. Phys. J. D (2015) 69: 201
https://doi.org/10.1140/epjd/e2015-50747-x

Regular Article

Optical unidirectional transmission in metal slit structures caused by convergent and shield effects

¹ Center for Theoretical Physics, Department of PhysicsCapital Normal University, Beijing 100048, P.R. China
² Department of Physics, Tsinghua University, Beijing 100084, P.R. China

^a e-mail: zyspaper@sina.com
^b e-mail: 263zys@263.net

Received: 11 October 2014
Received in final form: 30 April 2015
Published online: 21 August 2015

Abstract

One kind of optical unidirectional transmission structures is proposed which is composed of a metal subwavelength slit dressed by one or two gratings. Simulation results show that the gratings with different geometry parameters can play different roles. One role is the convergence effect and the other is shield effect. Each effect can independently cause the unidirectional transmission with special properties. These two effects are explained in view of optical reciprocal theorem. Combination of the two effects results in excellent unidirectional transmission properties.