Multichannel optical diode with unidirectional diffraction relevant total transmission

Abstract

We will show that broadband unidirectional optical transmission with a total transmission maximum inside the band can be obtained for linearly polarized incident waves in the nonsymmetric photonic crystal gratings made of isotropic linear materials at a fixed nonzero or zero angle of incidence. Being based on the merging of diffraction and dispersion effects, the basic physical mechanism studied exploits the transmission channels associated with higher orders, for which asymmetry in the coupling conditions at the two grating interfaces appears when spatial inversion symmetry is broken. Total transmission in one direction and zero transmission in the opposite direction can be obtained due to hybridization of Fabry-Perot type resonances with a diffraction anomaly that yields a diode-like operation regime. Single-beam deflection and two-beam splitting can be obtained, for which transmission can be (nearly) total, if the corrugated side is illuminated. In contrast to the previous studies, it is also shown that unidirectional transmission can appear only at a fixed frequency and only due to diffractions, when total transmission occurs at the noncorrugated-side illumination, being in agreement with the Lorentz Lemma. ©2012 Optical Society of America

Dispersion irrelevant wideband asymmetric transmission in dielectric photonic crystal gratings

“…1) were suggested for transmission less than a decade ago [11] and then studied with the emphasis put on asymmetric transmission at zero and nonzero angles of incidence [6]. The advanced performances were later studied in various frequency ranges from acoustic to optical ones [7,9,10,12].In the direct regime [10], the wideband unidirectionality with high forward-case transmittance (corrugated-side illumination), T → ≠ 0, and vanishing backward-case transmittance (noncorrugated-side illumination), T ← 0, occurs while zero order (symmetric) transmission is suppressed, t → 0 t ← 0 0. This regime is realizable in the nonsymmetric PhC gratings due to the common effect of diffraction and dispersion of FB modes.…”

Effects of Dielectric Substrate on Polarization Conversion Using Coupled Metasurfaces With and Without Tunneling

“…For the twisted metasurfaces, they can be obtained by involving polarization states different from the incident one [16-18, 22, 29]. Diodelike asymmetric transmission with reflections vanishing for one of two opposite incidence directions has been theoretically predicted in the zero-loss approximation for both diffraction [30] and polarization conversion [1,23] inspired mechanisms. The principal possibility of the perfect polarization conversion in a generalized doublelayer structure has been demonstrated [31].…”

One-way reciprocal spoof surface plasmons and relevant reversible diodelike beaming

“…Instead, only isotropic, linear, and passive materials are required. The diffraction relevant asymmetric transmission can be obtained in nonsymmetric photonic [19][20][21] and sonic 22 crystals, and nonsymmetric gratings that contain ultralow-index material layers. 23 In turn, the polarization conversion relevant mechanism is associated, first of all, with subwavelength and resonator based chiral metamaterials.…”