scholarly journals Magnetic plasmon resonances in nanostructured topological insulators for strongly enhanced light–MoS2 interactions

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Hua Lu ◽  
Zengji Yue ◽  
Yangwu Li ◽  
Yinan Zhang ◽  
Mingwen Zhang ◽  
...  
Keyword(s):  
Magnetic Materials ◽  
Topological Insulators ◽  
Theoretical Calculations ◽  
Incident Light ◽  
Building Blocks ◽  
Visible Range ◽  
High Frequencies ◽  
Plasmon Resonances ◽  
Magnetic Plasmon ◽  
Magnetic Resonances

AbstractMagnetic resonances not only play crucial roles in artificial magnetic materials but also offer a promising way for light control and interaction with matter. Recently, magnetic resonance effects have attracted special attention in plasmonic systems for overcoming magnetic response saturation at high frequencies and realizing high-performance optical functionalities. As novel states of matter, topological insulators (TIs) present topologically protected conducting surfaces and insulating bulks in a broad optical range, providing new building blocks for plasmonics. However, until now, high-frequency (e.g. visible range) magnetic resonances and related applications have not been demonstrated in TI systems. Herein, we report for the first time, to our knowledge, a kind of visible range magnetic plasmon resonances (MPRs) in TI structures composed of nanofabricated Sb2Te3 nanogrooves. The experimental results show that the MPR response can be tailored by adjusting the nanogroove height, width, and pitch, which agrees well with the simulations and theoretical calculations. Moreover, we innovatively integrated monolayer MoS2 onto a TI nanostructure and observed strongly reinforced light–MoS2 interactions induced by a significant MPR-induced electric field enhancement, remarkable compared with TI-based electric plasmon resonances (EPRs). The MoS2 photoluminescence can be flexibly tuned by controlling the incident light polarization. These results enrich TI optical physics and applications in highly efficient optical functionalities as well as artificial magnetic materials at high frequencies.

Bilayer PMMA antireflective coatings via microphase separation and MAPLE

2020 ◽  
Vol 41 (2) ◽  
pp. 164-173
Author(s):  
Yunlong Guo ◽  
Shuzhen Ren
Keyword(s):  
Microphase Separation ◽  
Incident Light ◽  
Visible Range ◽  
Laser Evaporation ◽  
Antireflective Coatings ◽  
Porous Network ◽  
Cross Sectional ◽  
Polymer Thin Film ◽  
Deposition Parameters ◽  
Surface Morphologies

Abstract A poly(methyl methacrylate) (PMMA) bilayer antireflective coating (ARC) is designed based on polymeric microphase separation and matrix-assisted pulsed laser evaporation (MAPLE). The spin-coated layer shows subwavelength porous network structures, after phase separation via annealing and removal of the polystyrene (PS) phase, while the MAPLE deposited surface layer exhibits a biomimic moth-eye structure on glass to trap the incident light. The elaborate spin coated structure can be controlled flexibly by changing the ratio of mixture, annealing time and temperature, and the moth-eye structure can also be tuned by deposition parameters. The transmittance of the ARC presents a maximum of 95.64% and an average of 94.81% in visible range. The moth-eye structure on glass substrate formed by nanoglobules makes positive contributions to the improvement of transmittance according to UV–Vis result and simulation. The wetting motion of PMMA globules is observed as well by the comparison of AFM surface morphologies and cross-sectional profiles of globules on glass and polymer thin film. This work is a novel attempt to fabricate bilayer ARC with two different structures by a single polymeric material and will provide new route for fabrication of multilayer ARCs.

Certification of normal samples of magnetic materials at high frequencies

1970 ◽  
Vol 13 (12) ◽  
pp. 1869-1874
Author(s):  
A. F. Kugaevskii ◽  
N. N. Chernousova
Keyword(s):  
Magnetic Materials ◽  
High Frequencies

scholarly journals Optical Properties of Spin-Coated TiO2Antireflection Films on Textured Single-Crystalline Silicon Substrates

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ryosuke Watanabe ◽  
Yohei Eguchi ◽  
Takuya Yamada ◽  
Yoji Saito
Keyword(s):  
Optical Properties ◽  
Crystalline Silicon ◽  
Low Cost ◽  
Incident Light ◽  
Antireflection Coating ◽  
Silicon Wafers ◽  
Reflectance Spectra ◽  
Visible Range ◽  
Single Crystalline Silicon ◽  
Single Crystalline

Antireflection coating (ARC) prepared by a wet process is beneficial for low cost fabrication of photovoltaic cells. In this study, we investigated optical properties and morphologies of spin-coated TiO2ARCs on alkaline textured single-crystalline silicon wafers. Reflectance spectra of the spin-coated ARCs on alkaline textured silicon wafers exhibit no interferences and low reflectance values in the entire visible range. We modeled the structures of the spin-coated films for ray tracing numerical calculation and compared numerically calculated reflectance spectra with the experimental results. This is the first report to clarify the novel optical properties experimentally and theoretically. Optical properties of the spin-coated ARCs without interference are due to the fractional nonuniformity of the thickness of the spin-coated ARCs that cancels out the interference of the incident light.

scholarly journals Highly efficient oxygen evolution reaction via facile bubble transport realized by three-dimensionally stack-printed catalysts

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ye Ji Kim ◽  
Ahyoun Lim ◽  
Jong Min Kim ◽  
Donghoon Lim ◽  
Keun Hwa Chae ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Specific Activity ◽  
Theoretical Calculations ◽  
Nanostructured Catalysts ◽  
Building Blocks ◽  
Utilization Efficiency ◽  
Active Surface Area ◽  
Mass Activity

Abstract Despite highly promising characteristics of three-dimensionally (3D) nanostructured catalysts for the oxygen evolution reaction (OER) in polymer electrolyte membrane water electrolyzers (PEMWEs), universal design rules for maximizing their performance have not been explored. Here we show that woodpile (WP)-structured Ir, consisting of 3D-printed, highly-ordered Ir nanowire building blocks, improve OER mass activity markedly. The WP structure secures the electrochemically active surface area (ECSA) through enhanced utilization efficiency of the extended surface area of 3D WP catalysts. Moreover, systematic control of the 3D geometry combined with theoretical calculations and various electrochemical analyses reveals that facile transport of evolved O2 gas bubbles is an important contributor to the improved ECSA-specific activity. The 3D nanostructuring-based improvement of ECSA and ECSA-specific activity enables our well-controlled geometry to afford a 30-fold higher mass activity of the OER catalyst when used in a single-cell PEMWE than conventional nanoparticle-based catalysts.

scholarly journals Polarization-Independent Metasurface Lens Based on Binary Phase Fresnel Zone Plate

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1467
Author(s):  
Xing Li ◽  
Jing Tang ◽  
Jonathan Baine
Keyword(s):  
Fresnel Zone ◽  
Incident Light ◽  
Polarization State ◽  
Zone Plate ◽  
Visible Range ◽  
Fresnel Zone Plate ◽  
Binary Phase ◽  
Nanophotonic Devices ◽  
Potential Applications ◽  
Polarization Independent

Based on the binary phase Fresnel zone plate (FZP), a polarization-independent metasurface lens that is able to focus incident light with any polarization state, including circular, linear, and elliptical polarizations, has been proposed and investigated. We demonstrate that the metasurface lens consisting of metal subwavelength slits can operate in a wide bandwidth in the visible range, and has a higher focusing efficiency than that of an amplitude FZP lens without phase modulation. A multi-focus FZP metasurface lens has also been designed and investigated. The proposed lens can provide potential applications in integrated nanophotonic devices without polarization limitations.

scholarly journals Planning Optimization of the Work Processes of Gas Cleaning Facilities of a Power Plant by Means of Mathematical Processing and Computer Simulation

2018 ◽  
Vol 41 ◽  
pp. 02011 ◽  
Author(s):  
Olesya Aksenova ◽  
Evgenia Nikolaeva
Keyword(s):  
Computer Simulation ◽  
Power Plant ◽  
Computer Modeling ◽  
Power Plants ◽  
Theoretical Calculations ◽  
Building Blocks ◽  
Design Stage ◽  
Work Processes ◽  
Gas Cleaning ◽  
Mathematical Processing

The article seeks to examine the efficiency of applying means of mathematical processing and computer modeling of the work processes of gas cleaning facilities of power plants to optimize the process of planning and designing of future power plant in operation. A way of solution of the gas outbursts cleaning problem at the stage of designing measures for the development of waste processing systems through mathematical processing of expected volumes of gas outbursts and computer simulation of individual pieces of equipment and working areas as a whole is offered. The authors present the results of the processing of the projected technological processes and the gas outbursts cleaning facilities in terms of E-networks and using mathematical processing in the application Simulink, which allows to build a model of the device and to carry out calculations on the screen using the library of building blocks. A 3D model of the gas cleaning facilities, which allows to visualize the technological process and to compare it with theoretical calculations at the design stage of the future power plant and, if necessary, make changes to the project, has been created by means of computer modeling.

scholarly journals A domain-specific language and matrix-free stencil code for investigating electronic properties of Dirac and topological materials

2020 ◽  
Vol 35 (1) ◽  
pp. 60-77
Author(s):  
Andreas Pieper ◽  
Georg Hager ◽  
Holger Fehske
Keyword(s):  
Topological Insulators ◽  
Sparse Matrix ◽  
Building Blocks ◽  
Domain Specific Language ◽  
Code Generator ◽  
Specific Language ◽  
Domain Specific ◽  
Topological Materials ◽  
Multiple Data ◽  
Matrix Free

We introduce PVSC-DTM (Parallel Vectorized Stencil Code for Dirac and Topological Materials), a library and code generator based on a domain-specific language tailored to implement the specific stencil-like algorithms that can describe Dirac and topological materials such as graphene and topological insulators in a matrix-free way. The generated hybrid-parallel (MPI+OpenMP) code is fully vectorized using Single Instruction Multiple Data (SIMD) extensions. It is significantly faster than matrix-based approaches on the node level and performs in accordance with the roofline model. We demonstrate the chip-level performance and distributed-memory scalability of basic building blocks such as sparse matrix-(multiple-) vector multiplication on modern multicore CPUs. As an application example, we use the PVSC-DTM scheme to (i) explore the scattering of a Dirac wave on an array of gate-defined quantum dots, to (ii) calculate a bunch of interior eigenvalues for strong topological insulators, and to (iii) discuss the photoemission spectra of a disordered Weyl semimetal.

scholarly journals Apertureless scanning near-field optical microscopy of sparsely labeled tobacco mosaic viruses and the intermediate filament desmin

2013 ◽  
Vol 4 ◽  
pp. 510-516 ◽  
Author(s):  
Alexander Harder ◽  
Mareike Dieding ◽  
Volker Walhorn ◽  
Sven Degenhard ◽  
Andreas Brodehl ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Fluorescence Imaging ◽  
Intermediate Filament ◽  
Dipolar Coupling ◽  
Incident Light ◽  
Near Field ◽  
Building Blocks ◽  
Atomic Scale ◽  
Intermediate Filament Protein ◽  
Wide Range

Both fluorescence imaging and atomic force microscopy (AFM) are highly versatile and extensively used in applications ranging from nanotechnology to life sciences. In fluorescence microscopy luminescent dyes serve as position markers. Moreover, they can be used as active reporters of their local vicinity. The dipolar coupling of the tip with the incident light and the fluorophore give rise to a local field and fluorescence enhancement. AFM topographic imaging allows for resolutions down to the atomic scale. It can be operated in vacuum, under ambient conditions and in liquids. This makes it ideal for the investigation of a wide range of different samples. Furthermore an illuminated AFM cantilever tip apex exposes strongly confined non-propagating electromagnetic fields that can serve as a coupling agent for single dye molecules. Thus, combining both techniques by means of apertureless scanning near-field optical microscopy (aSNOM) enables concurrent high resolution topography and fluorescence imaging. Commonly, among the various (apertureless) SNOM approaches metallic or metallized probes are used. Here, we report on our custom-built aSNOM setup, which uses commercially available monolithic silicon AFM cantilevers. The field enhancement confined to the tip apex facilitates an optical resolution down to 20 nm. Furthermore, the use of standard mass-produced AFM cantilevers spares elaborate probe production or modification processes. We investigated tobacco mosaic viruses and the intermediate filament protein desmin. Both are mixed complexes of building blocks, which are fluorescently labeled to a low degree. The simultaneous recording of topography and fluorescence data allows for the exact localization of distinct building blocks within the superordinate structures.

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