Diffraction inspired unidirectional and bidirectional beam splitting in defect-containing photonic structures without interface corrugations

Abstract

It is shown that strong diffractions and related dual-beam splitting can be obtained at transmission through the nonsymmetric structures that represent two slabs of photonic crystal (PhC) separated by a single coupled-cavity type defect layer, while there are no grating-like corrugations at the interfaces. The basic operation regimes include unidirectional and bidirectional splitting that occur due to the dominant contribution of the first positive and first negative diffraction orders to the transmission, which is typically connected with different manifestations of the asymmetric transmission phenomenon. Being the main component of the resulting transmission mechanism, diffractions appear owing to the effect exerted by the defect layer that works like an embedded diffractive element. Two mechanisms can co-exist in one structure, which differ, among others, in that whether dispersion allows coupling of zero order to a wave propagating in the regular, i.e., defect-free PhC segments or not. The possibility of strong diffractions and efficient splitting related to it strongly depend on the dispersion properties of the Floquet-Bloch modes of the PhC. Existence of one of the studied transmission scenarios is not affected by location of the defect layer.

Thermally sensitive scattering of terahertz waves by coated cylinders for tunable invisibility and masking

“…Effects of phase as well as those of bright and dark LSPRs are planned for future studies in the context of the discussed scattering scenarios. The richness of the palette of achievable effects is promising for multifunctionality, i.e., when either two functions are combined in one spectral regime, or different functions are realized in different spectral regimes, in one device [48][49][50].…”

Single–Band and Multiband Angular Filtering Using Two–Dimensional Photonic Crystals and One–Layer Gratings

“…It is worth noting that also for reflection mode, nearly perfect efficiency can be kept in a large region in .kL; Â/-plane, so that strong selectivity with respect to  is expected to occur also for relatively narrow incident beams, although the boundaries of the bands can be stronger blurred in this case. When a nonsymmetric PhC grating is used in reflection mode, different regimes of diffraction inspired asymmetric transmission may appear in the neighboring frequency ranges [31,40].…”

Two types of single-beam deflection and asymmetric transmission in photonic structures without interface corrugations

“…Until now, single-beam deflection has been studied in PhC-based structures with a corrugated interface that imposes significant restrictions on the resulting design. At the same time, the recent results on dual-beam unidirectional splitting, another regime inspired by diffractions, indicate the possibility of strong diffractions in photonic structures without a corrugated interface [33].…”