Article
Engineering, Electrical & Electronic
Seyedeh Leila Mortazavifar, Mohammad Reza Salehi, Mojtaba Shahraki
Summary: This paper provides a theoretical design and circuit model details for a square- and circle-shaped broadband perfect ring absorber. The absorber, with a three-layered structure made up of tungsten, silica, and tungsten, achieves ultra-broadband absorption responses in different wavelength ranges. The results demonstrate the high absorption performance of the optimized design, which is related to tungsten.
JOURNAL OF ELECTRONIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Jiayi Jiang, Yan Cao, Xin Zhou, Haixia Xu, Kexin Ning, Xuan Xiao, Yanxin Lu, Cairong Ding, Yihang Chen, Jianwen Dong
Summary: In this study, a metasurface broadband perfect absorber with an ultrathin thickness of 148 nm and a large area of around 10 cm(2) was experimentally demonstrated. The absorption efficiency of this absorber exceeded 97% in the wavelength range of 400 to 800 nm. The broadband absorption was attributed to the overlapped resonances of Fabry-Perot, surface plasmon polariton, and localized surface plasmons. These findings provide a novel technique for the manufacturing of absorption-based devices at wafer-scale and low cost for applications such as high-contrast imaging and optical modulation.
Article
Thermodynamics
Mohamad Abou Houran, Ammar Armghan, Muhammad Abuzar Baqir, Khaled Aliqab, Muhammad Saqlain, Meshari Alsharari
Summary: This paper presents a wideband MXene-based metamaterial absorber made of subwavelength-sized periodic nanorods of MXene operating in the infrared regime. The absorber shows absorption of above 80% over a wide range, from 1150 to 2500 nm, due to localized surface plasmonic resonance (LSPR) of the top metasurface of periodic nanorods. The MXene-based optical absorber features a polarization-insensitive nature and demonstrates stable absorption for obliquity incident angles up to 50 degrees.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Electrical & Electronic
Vikram Maurya, Sarthak Singhal
Summary: A multiband electromagnetic terahertz absorber is proposed as a biosensor in this paper. The absorber consists of a metallic resonator loaded with multiple ringshaped slots, dielectric material, and a metallic ground plane. It has multiple absorption peaks at different terahertz frequencies, high absorption rate and wide absorption peak width, and is independent of polarization. The proposed absorber can be used for detecting malaria, cancer cells, and tumor cells, and can effectively estimate the refractive index of unknown samples.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Manish Mathew Tirkey, Nisha Gupta
Summary: This article presents a cost-effective, conformal, polarization-insensitive electromagnetic wave absorber with ultrathin and ultrawideband characteristics. It achieves over 90% absorptivity and is suitable for conformal applications.
IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY
(2022)
Article
Materials Science, Multidisciplinary
Bingzhen Li, Yuhua Chen, Qingqing Wu, Yan Li, Yaxing Wei, Jijun Wang, Fangyuan Li, Xinwei Liu
Summary: A novel ultrathin narrowband metasurface absorber with bidirectional perfect absorption properties is proposed in this study, based on a tri-layer metal square-circular-square patch (SCSP) structure. Simulation results demonstrate a remarkable absorbance of 98.1% for the proposed absorber, which is consistent with experimental and theoretical calculations. The absorber exhibits stable wide-angle absorption properties for both TE and TM waves under various oblique incidence angles.
Article
Optics
Xun Wang, Tian Sang, Guoqing Li, Qing Mi, Yao Pei, Yueke Wang
Summary: A novel ultrabroadband and ultrathin absorber based on the encapsulated T-shaped metasurface (ETM) has been designed, fabricated, and characterized. The ETM exhibits robust absorption performance with improved impedance matching and can achieve ultrabroadband absorption through the excitation of localized surface plasmon. Additionally, the ETM shows polarization-insensitive and wide-angle features, making it suitable for various potential applications.
Article
Multidisciplinary Sciences
Qinyu Qian, Pengfei Liu, Li Fan, Liang Zhao, Chinhua Wang
Summary: A non-sharp-corner quarter wave plate (NCQW) structured by an Ag hollow elliptical ring array is reported, with strong localized surface plasmons (LSP) resonances excited in the single layer of 8 nm thickness. By manipulating the parameters of the hollow elliptical ring, the transmitted amplitude and phase of the two orthogonal components are effectively controlled. This NCQW achieves a phase difference of pi/2 and an amplitude ratio of 1 simultaneously at the wavelength of 834 nm with a transmission of 0.46, and works well in an ultrawide wavelength band of 110 nm, showing great potential for advanced nanophotonic devices and integrated photonic systems.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Ran Wang, Song Yue, Zhe Zhang, Yu Hou, Hongda Zhao, Shitian Qu, Man Li, Zichen Zhang
Summary: This paper numerically demonstrates a broadband perfect absorber in the visible range, which has a high absorptance and potential applications in photovoltaics and photodetection.
Article
Engineering, Electrical & Electronic
Jaymit Surve, Juveriya Parmar, Shobhit K. Patel, Rajendrasinh Jadeja
Summary: The graphene-based metasurface solar absorber shows excellent absorption performance for the broadband visible wavelength range. By exploring different designs and parameter variations, the highest average absorption is achieved for the four C-shape array metasurface absorber design. With good absorption efficiency in the ultraviolet, visible, and infrared regions with wavelengths ranging from 0.2 to 0.8 µm, it can be applied to photovoltaic and solar energy harvesting applications.
OPTICAL AND QUANTUM ELECTRONICS
(2021)
Article
Optics
Naveen Kumar Maurya, Jayanta Ghosh, P. Sumithra
Summary: This study presents a graphene-based ultra-wideband metasurface for terahertz applications. The metasurface is ultra-thin and tunable with a high absorption bandwidth of 13.9 THz. The designed unit cell has structural symmetry and is polarization insensitive to normal incidence, making it suitable for various terahertz regime applications.
Article
Engineering, Electrical & Electronic
Nafiseh Malekshahi, Amir Amini, Iman Chaharmahali
Summary: This work presents a four-layer absorber based on graphene patterns, which is validated through simulations and shown to achieve wideband absorption in the 8-9.5 THz frequency range.
JOURNAL OF COMPUTATIONAL ELECTRONICS
(2021)
Article
Optics
Xiaokun Yang, Xueheng Zhang, Zhao Ding, Zhengping Zhang
Summary: This paper proposes a sextuple-band EM absorber with absorptivity over 90% within 5 bands from S to K. The absorber is made of inexpensive FR4 material with an ultrathin substrate of only 1 mm. By combining 3 different geometries and introducing an "A"-shaped improver, the absorptivity of all bands is raised to 90% or above. An equivalent circuit model is established to further demonstrate the multiple band characteristics. A prototype is fabricated and measured, showing consistent results with simulation. This work can be considered an excellent candidate for radar cross-section reduction, frequency selection surface, cloaking material, etc.
Article
Physics, Multidisciplinary
Abhishek Kumar, Gaurav Varshney
Summary: This paper presents an ultrathin structure of graphene-based absorber that is implemented and numerically analyzed. The absorber is designed using graphene ring resonators and reflectors in the lower terahertz frequency ranges. By utilizing concentric graphene ring resonators and adjusting the chemical potential of graphene, multiple resonances are generated and a broad absorption band is achieved. The proposed absorber achieves over 90% absorption in the frequency range of 10.34-16.23 THz and over 80% absorption in the frequency range of 9.89-16.77 THz. It also allows for polarization independent geometry and incident angles up to 50 degrees.
Article
Physics, Multidisciplinary
Zeyong Wei, Hongkun Li, Weijie Xu, Yang Cao
Summary: High impedance metasurface is an artificial structure capable of highly efficient absorption of electromagnetic waves, and the absorption frequency can be dynamically controlled by adjusting the bias voltage. By loading diodes between periodic gratings and applying positive bias, it is possible to achieve absorption of most of the incident wave at the resonant frequency.
FRONTIERS IN PHYSICS
(2021)
Article
Optics
Mojtaba Shahraki, Mohammad Reza Salehi, Ebrahim Abiri
JOURNAL OF MODERN OPTICS
(2017)
Article
Materials Science, Multidisciplinary
Seyedeh L. Mortazavifar, Mohammad R. Salehi, Mojtaba Shahraki, Ebrahim Abiri
Summary: The optical absorption of rectangular a-Si/c-Si solar cells was investigated, and the proposed structure showed high absorption rate despite its simple geometry. Broadband absorption was achieved using irregularities in the nanowires.
JOURNAL OF PHOTONICS FOR ENERGY
(2021)
Article
Engineering, Electrical & Electronic
Mojtaba Shahraki, Hossein Malekpoor
Summary: This paper investigates the effect of linear polarization on Soliton interactions in highly birefringent optical fibers. The results show that the interaction between polarized Solitons is different from the interaction between unpolarized Solitons. The paper explores the impact of different variables on Soliton interactions and performs an optimization process to minimize the interaction between two polarized Solitons.
OPTICAL AND QUANTUM ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Hossein Malekpoor, Mojtaba Shahraki
Summary: This study introduces a low profile printed slot antenna backed by broadband planar artificial magnetic conductor (AMC) to improve radiation efficiency and bandwidth. Compared to the antenna without AMC, the suggested antenna with AMC exhibits a smaller size, enhanced bandwidth, and excellent impedance matching with uni-directional radiation patterns.
JOURNAL OF COMMUNICATIONS TECHNOLOGY AND ELECTRONICS
(2022)
Article
Optics
Seyedeh Leila Mortazavifar, Mohammad Reza Salehi, Mojtaba Shahraki, Ebrahim Abiri
Summary: The present study proposes an elliptical silicon array for broadband absorption inside ultra-thin silicon solar cells. The efficient design of irregular nanowires can improve the absorption capacity, but it requires a trade-off between optical antenna effects and diffraction effects within nanowire arrays. A structure composed of semi-periodic nanowires is suggested to enhance the performance of ultra-thin silicon solar cells.
JOURNAL OF MODERN OPTICS
(2022)
Article
Nanoscience & Nanotechnology
Mojtaba Shahraki, Hossein Malekpoor
Summary: The effects of grating structure on the performance of PTB7: PC70BM organic solar cells were studied. It was found that using dissimilar gratings inside the active area of the solar cell could increase the short circuit current density. However, conducting optimization processes based on particle swarm optimization algorithm revealed that the highest achievable increase in J(SC) for a three-grating structure was only 3.2% compared to a single structure grating. Therefore, the grating structure was applied to the antireflection coating (ARC) layer of the solar cell, and it was observed that using a Gaussian grating ARC layer could significantly increase the overall J(SC) of the solar cell.
JOURNAL OF NANOPHOTONICS
(2022)
Article
Astronomy & Astrophysics
Hossein Malekpoor, Mojtaba Shahraki
Summary: This article introduces a novel printed dipole antenna array with a rhomboid AMC reflector, which can achieve a wider bandwidth in the range of 5.27-6.74 GHz and exhibits smaller size, higher gain, and better impedance matching compared to the antenna without AMC.
Article
Engineering, Electrical & Electronic
Seyedeh Leila Mortazavifar, Mohammad Reza Salehi, Mojtaba Shahraki, Ebrahim Abiri
Summary: This paper investigates the effects of dimensions and arrangements of stadium silicon nanowires (NWs) on their absorption properties. It proposes a simple geometric structure with comparable absorption rate to complex structures. Changing the cross-section shape of NW from circular (or rectangular) to a stadium shape alters the position and number of absorption modes. The use of multiple NWs with different geometries achieves broadband absorption, with the maximum enhancement observed in non-close packed NWs. Particle swarm optimizations are used to optimize the structures. The findings have implications for improving the absorption of solar cells without introducing additional absorbent materials.
FRONTIERS OF OPTOELECTRONICS
(2022)
Article
Computer Science, Interdisciplinary Applications
Mojtaba Shahraki, Farzad Shahabian, Ali Maghami
Summary: This article presents a unified scheme for applying nonlinear dynamic time integration methods. Various time integration methods are investigated and a unified scheme for single-point and multi-point methods is presented. The performance of the multi-point methods as nonlinear solution methods is also investigated.
ENGINEERING WITH COMPUTERS
(2023)
Article
Engineering, Electrical & Electronic
Seyedeh Leila Mortazavifar, Mohammad Reza Salehi, Mojtaba Shahraki
Summary: This paper provides a theoretical design and circuit model details for a square- and circle-shaped broadband perfect ring absorber. The absorber, with a three-layered structure made up of tungsten, silica, and tungsten, achieves ultra-broadband absorption responses in different wavelength ranges. The results demonstrate the high absorption performance of the optimized design, which is related to tungsten.
JOURNAL OF ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Hossein Malekpoor, Mojtaba Shahraki
Summary: This study introduces two new designs of reduced size broadband microstrip patch antennas for ultra-wideband operation. The antennas are configured with folded triangular patches' feeding technique, V-shaped slot, half V-shaped slot, and shorting pins. The V-shaped slot design achieves an impedance bandwidth of 3.91-12 GHz, while the half V-shaped slot design improves the impedance bandwidth from 4 to 17.22 GHz.
ADVANCED ELECTROMAGNETICS
(2021)
Article
Materials Science, Multidisciplinary
Mohammad Reza Salehi, Mojtaba Shahraki, Ebrahim Abiri
CURRENT APPLIED PHYSICS
(2017)