The first observation to the authors' knowledge of electromagnetic surface waves in a two-dimensional dielectric crystal is reported. By using the coherent microwave transient spectroscopy technique, surface waves are shown to exist at frequencies within the photonic band gap for certain lattice terminations. Energy at gigahertz frequencies is coupled into the surface mode using a prism coupling technique. The experimental results are in excellent agreement with theoretical predictions.
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http://dx.doi.org/10.1364/ol.18.000528 | DOI Listing |
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January 2025
Department of Chemistry, Dr. Vishwanath Karad MIT World Peace University, Survey No, 124, Paud Rd, Kothrud, Pune, Maharashtra, 411038, India.
Surface Plasmon Polaritons (SPPs) and Localized Surface Plasmon Resonances (LSPRs) are fundamental phenomena in plasmonics that enable the confinement of electromagnetic waves beyond the diffraction limit. This confinement results in a significant enhancement of the electric field, making this phenomenon particularly beneficial for sensitive detection applications. However, conventional plasmonic sensors face several challenges, notably their difficulty in distinguishing chiral molecules, which are vital in drug development.
View Article and Find Full Text PDFNanophotonics
January 2025
Key Laboratory for Information Science of Electromagnetic Waves, School of Information Science and Technology, Fudan University, Shanghai 200433, China.
Gesture recognition plays a significant role in human-machine interaction (HMI) system. This paper proposes a gesture-controlled reconfigurable metasurface system based on surface electromyography (sEMG) for real-time beam deflection and polarization conversion. By recognizing the sEMG signals of user gestures through a pre-trained convolutional neural network (CNN) model, the system dynamically modulates the metasurface, enabling precise control of the deflection direction and polarization state of electromagnetic waves.
View Article and Find Full Text PDFUltrasonics
January 2025
Institut Langevin, ESPCI Paris, Université PSL, CNRS, 1 rue Jussieu, Paris, 75005, France.
Detecting surface contamination on thin thermoformed polymer plates is a critical issue for various industrial applications. Lamb waves offer a promising solution, though their effectiveness is challenged by the strong attenuation and anisotropy of the polymer plates. This issue is addressed in the context of a calcium carbonate (CaCO) layer deposited on a polypropylene (PP) plate.
View Article and Find Full Text PDFBiopolymers
March 2025
Centro de Investigación en Química Aplicada, Saltillo, Coahuila, Mexico.
Exploring new ecological and simultaneous processes to modify wood fibers (WF) by-products is a required pathway toward circular economy and sustainability. Thus, plasma-activated water (PAW) and ultrasound (U) were employed as alternative methods to modify WF in a continuous process. Such treatments promoted the etching and cavities on the WF surface that destabilized the hydrogen bonds of the hemicellulose and lignin molecules, increasing the cellulose fraction.
View Article and Find Full Text PDFSci Total Environ
January 2025
Programa de Pós-Graduação em Clima e Ambiente, Instituto Nacional de Pesquisas da Amazônia, Universidade do Estado do Amazonas, Av. André Araújo, 2936, Bairro Aleixo, 69060-001 Manaus, AM, Brazil.
The teleconnections between El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and Tropical North Atlantic warming (+TNA) play a critical role in characterizing extreme drought events in the Amazon Basin (AB). This study examines the seven most recent drought extreme events up to 2023, using seasonal composites of the sea surface temperature and atmospheric variables over a five-quarter period starting at the austral spring(-1) of the year preceding that when the lowest water level at Manaus port was recorded. Two distinct patterns emerge, driven by consecutive ENSO events with opposite phases, referred to as cyclic La Niña-El Niño and cyclic El Niño-La Niña drought events.
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