Quasicrystal (QC) metamaterials have attracted considerable attention due to their unique optical properties resulting from their aperiodic but ordered structure. Unlike periodic crystals, QCs possess high-order symmetry, which leads to in-plane isotropic properties and the possibility of creating photonic bandgap structures. In this paper, we investigate tunable absorbing films based on the lattice structure of AlCuFe quasicrystal, which exhibit high quality (Q) and refractive index sensitivity.
Fabricated using thin-film deposition techniques, these structures consist of thin AlCuFe layers deposited on a dielectric substrate and arranged in a lattice of quasi-crystalline geometry. By fine-tuning the lattice parameters, such as the period and thickness of the layers, resonant absorption can be achieved in the desired wavelength range. Finite element method (FEM) calculations have shown that the developed structures exhibit narrow absorption bands with a high Q-factor, indicating strong light-matter interactions.
Due to the active development of terahertz technology and materials science, special attention is paid to terahertz absorbing structures. In this paper, a tunable absorbing film with a periodic structure based on an AlCuFe quasicrystal is proposed. This film consists of an AlCuFe quasicrystalline lattice and a gold substrate, which simplifies its manufacture. The film exhibits three pronounced absorption bands in a given frequency range. When the polarization of the incident radiation changes, it is transformed into an ideal absorber with one absorption band. Impedance analysis shows that it is close to the impedance of free space in the absorption bands, which agrees with theoretical calculations. The study of the electric field shows that the absorption of electromagnetic waves is due to the resonance of the guiding film and the effect of localized surface plasmon resonance (LSPR). The film has excellent tuning characteristics, a high Q value and sensitivity. The maximum quality factor reaches 242, and the sensitivity to refractive index change exceeds 2700, reaching 4032. Overall, the absorbing film has great potential for application in biomedicine and communication technologies.
The terahertz range, which covers frequencies from 0.1 to 10 THz, plays an important role in astrophysics. Studies have shown that the spectra of many macromolecules and crystals lie in the terahertz range, making it a valuable tool in medicine and microphysics. In addition, terahertz waves are promising for communications, since their attenuation in air is less than in the microwave and infrared ranges. This emphasizes the need to develop effective absorbers and sensors of terahertz radiation.
In addition, it was found that the resonance properties of these films are strongly dependent on the refractive index of the surrounding medium. Small changes in the refractive index lead to a significant shift in the resonant frequency, making these structures promising for applications in sensors and biosensors. The refractive index sensitivity can be further increased by optimizing the lattice geometry and choice of materials.
In conclusion, the presented tunable absorber films based on AlCuFe quasicrystal show promising performance for various optical and sensor applications. Their high Q-factor, refractive index sensitivity and tunability make them an attractive platform for developing advanced photonic devices.
Author: Wenxin Li, Yahui Liu, Le Ling, Zhongxi Sheng, Shubo Cheng, Zao Yi, Pinghui Wu, Qingdong Zeng, Bin Tang, Sohail Ahmad
Institute:
School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, Hubei 434023, China
Coal Technology & Engineering Research Institute China Coal Technology & Engineering Group Chongqing Research Institute Co., Ltd, Chongqing 401332, China
Dongfang Electric Group Research Institute, Chengdu 611731, China
Joint Laboratory of Material Properties under Extreme Conditions, Southwest University of Science and Technology, Mianyang 621010, China
Photonic Technology Research Center, Fujian Provincial Key Laboratory of Advanced Micro- and Nanophotonic Technology and Devices and Fujian Provincial Key Laboratory of Information Functional Materials for Higher Education, Quanzhou Normal University, Quanzhou 362000, China
School of Physics and Electronic Engineering, Hubei University of Engineering, Xiaogan 432000, China
School of Microelectronics and Control Engineering, Changzhou University, Changzhou 213164, China
Institute of Physics, Bahauddin Zakariya University, Multan 66000, Pakistan