We have studied theoretically and experimentally the influence of a dielectric substrate on the frequency-dependent terahertz electric near-field of a small hole in a metal layer. We find that the near-field transmission spectrum and the two-dimensional field distribution of an empty hole in a thin metal layer on a substrate are almost identical to that of a hole which is also filled with the same dielectric material as the substrate. For thicker metal layers, however, the near-field spectra of filled and unfilled holes become very different. In addition, for thick metal layers, the two-dimensional field distributions are more strongly affected by the substrate, especially if we allow for an air gap between the metal and the substrate. Our results validate the -somewhat unusual- two-dimensional field distribution measured beneath a hole in a thick metal foil and highlight the effect that a substrate can have on the measurement of the near-field of an object.
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http://dx.doi.org/10.1364/OE.17.017412 | DOI Listing |
Innovation (Camb)
January 2025
Department of Physics and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China.
Transmission electron microscopy (TEM) is an indispensable tool for elucidating the intrinsic atomic structures of materials and provides deep insights into defect dynamics, phase transitions, and nanoscale structural details. While numerous intriguing physical properties have been revealed in recently discovered two-dimensional (2D) quantum materials, many exhibit significant sensitivity to water and oxygen under ambient conditions. This inherent instability complicates sample preparation for TEM analysis and hinders accurate property measurements.
View Article and Find Full Text PDFAnal Chem
January 2025
Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany.
Compound-specific stable isotope analysis (CSIA) using liquid chromatography-isotope ratio mass spectrometry (LC-IRMS) is a powerful tool for determining the isotopic composition of carbon in analytes from complex mixtures. However, LC-IRMS methods are constrained to fully aqueous eluents. Previous efforts to overcome this limitation were unsuccessful, as the use of organic eluents in LC-IRMS was deemed impossible.
View Article and Find Full Text PDFAdv Mater
January 2025
Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan, 410082, China.
The exchange bias (EB) effect is a fundamental magnetic phenomenon, in which the exchange bias field/coercive field ratio (|H/H|) can improve the stability of spintronic devices. Two-dimensional (2D) magnetic heterostructures have the potential to construct low-power and high-density spintronic devices, while their typically air unstable and |H/H| lesser, limiting the possibility of applications. Here, 2D CrTe nanosheets have been systematically synthesized with an in situ formed ≈2 nm-thick Te doped CrO layer (Te-CrO) on the upper surface by chemical vapor deposition (CVD) method.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemistry, College of Science, King Saud University, PO Box 2455, Riyadh, 11541, Saudi Arabia.
The ongoing challenge of water pollution necessitates innovative approaches to remove organic contaminants from wastewater. In this work, new two-dimensional S-scheme heterojunction photocatalysts BiO/CdS and MoS/BiO/CdS that are intended for the effective photocatalytic destruction of 4-nitrophenol, a dangerous organic pollutant, are synthesized and characterized. Utilizing a solvothermal method, successfully generated these ternary nanocomposites, which were characterized through various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electronmicroscopy (HRTEM), Brunauer-Emmett-Telle (BET) and diffuse reflectance spectroscopy (DRS).
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Electrical Engineering, Southeast University, Nanjing 210096, China.
The electromagnetic characteristics of a single-phase permanent magnet linear oscillation actuator are analyzed by the finite element method. Firstly, the basic structure and operation principle of the linear oscillation actuator are introduced. The internal stator slot and arc tooth are used to reduce the detent force.
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