The Zenneck THz surface wave (Z-TSW) on metals is discussed with respect to its difficulty in generation and measurement. The spatial collapse of the extent of the Z-TSW evanescent field, upon the addition of a sub-wavelength dielectric layer on the metal surface, is explained by a simple model, in good agreement with exact analytical theory. Experimental measurements of the THz surface wave on an aluminum surface covered with a 12.5 microm thick dielectric layer have completely characterized the resultant single-mode dielectric layer THz surface wave (DL-TSW). The measured frequency-dependent exponential fall-off of the evanescent wave from the surface agrees well with theory. The DL-TSW frequency-dependent absorption coefficient, phase velocity, group velocity and group velocity dispersion have been obtained. These guided-wave parameters compare favorably with other guided wave structures.
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http://dx.doi.org/10.1364/OE.17.017088 | DOI Listing |
We demonstrate experimentally an efficient terahertz emitter that consists of a 20 µm thick layer of LiNbO clamped between a fused silica substrate and a Si semicone. A focused laser beam from an ultrafast optical oscillator propagates in the LiNbO layer and emits a Cherenkov cone of terahertz radiation to the Si semicone. The radiation is totally internally reflected by the semicone's convex surface and escapes the semicone through its base as a collimated beam.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Intelligent Equipment Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China. Electronic address:
Gender identification of chick embryos at the early stages of incubation is of significant importance to poultry industry. Existing studies showed reproductive hormone concentrations are associated with gender of chick embryos. Accurate detection of reproductive hormone concentration can assist in gender identification.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Zhangjiang Laboratory, Shanghai, 201204, China.
Boasting superior flexibility in beam manipulation and a simpler framework than traditional phased arrays, terahertz metasurface-based phased arrays show great promise for 5G-A/6G communication networks. Compared with the reflective reconfigurable intelligent surface (reflective RIS), the transmissive RIS (TRIS) offers more feasibility for transceiver multiplexing systems to meet the growing demand for high-performance beam tracking in terahertz communication and radar systems. However, the terahertz TRIS encounters greater challenges in phase shift, beam efficiency, and complex circuitry.
View Article and Find Full Text PDFHeliyon
December 2024
Faculty of Electrical and Computer Engineering, Semnan University, Semnan, Iran.
Optical sensors are among the most significant optical devices that have found extensive applications for THz sensing. Surface plasmon-based sensors have attracted increasing attention more than other kinds of optical sensors such as photonic crystal, optical fiber, and graphene sensors, owing to their compact footprint, fast reaction, and high sensitivity value. Therefore, this work reviews plasmonic sensor structures divided into three general categories.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Department of Chemistry, University of Graz, Heinrichstraße 28/IV, 8010 Graz, Austria.
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