Absorption characteristics of a typical photonic crystal unidirectional absorber under graphene modulation

Abstract

.Unidirectional absorbers have potential applications in infrared detection, energy conversion, and solar energy harvesting. In this work, the absorption properties of a typical photonic crystal (PC) unidirectional absorber in the visible- and near-infrared modulated by graphene are systematically investigated. This is achieved by placing a typical non-periodic PC in an air medium. When the electromagnetic wave is incident vertically, double peak absorption is formed at wavelengths of 560 nm as well as 755 nm. The achieved non-reciprocal absorption is attributed by the surface plasmon resonance between the semiconductor and metal defect layers. In this work, the effect of period numbers is discussed to improve absorption performance. Meanwhile, the role of the metal defect layer is explored by the variation of the electric field inside the device. And the unidirectional absorption performance was verified. In addition, the absorption characteristics of the two types of semi-conductor material devices are analyzed. Compared to existing unidirectional devices, this structure has the advantages of small size, high efficiency, wide bandwidth, and easy optoelectronic integration. This structure, based on its own absorption and emission characteristics, can facilitate the development of LIDAR stealth devices, and thus, the advancement of infrared radar steganography.

Near-IR unidirectional absorption in a tunable asymmetric one-dimensional photonic crystal with VO2 defect layers

“…inserted into the PC disrupting the original periodic structure, the corresponding defect energy levels will appear in the PBG and allow the passage of this part of the electromagnetic wave [3]. These properties give researchers the ability to control the spectral properties of structures, which is extremely valuable for applications such as thermoelectric conversion [4,5], infrared stealth [6][7][8], and thermal radiation modulation [9]. In the process of research and improvement of PC, researchers are more eager to master more approaches to adjust the spectral properties, among which achieving dynamic control of electromagnetic propagation is a popular area.…”