In C-2W, an elevated impurity concentration can lead to significant degradation of plasma performance and energy losses through radiation. To gauge plasma contamination from impurities, the effective ion charge ( ) can be determined from measurements of bremsstrahlung continuum radiation over a small spectral range free from line radiation. To this end, a diagnostic system including visible and near-infrared bremsstrahlung detectors was deployed in C-2W to measure time-dependent radial distributions of . The system is complemented by an array of survey spectrometers which enable full-range spectroscopic measurements of impurity emission lines from the vacuum ultraviolet to the near infrared, providing a good picture of the plasma composition. Here, the design scheme for this integrated diagnostic system is presented and discussed.
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http://dx.doi.org/10.1063/1.5037588 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119 China. Electronic address:
Non-optically active water quality parameters (NAWQPs) are essential for surface water quality assessments, although automated monitoring methods are time-consuming, include labor-intensive chemical pretreatment, and pose challenges for high spatiotemporal resolution monitoring. Advancements in spectroscopic techniques and machine learning may address these issues. We integrated ultraviolet-visible-near infrared absorption spectroscopy with physical-chemical measurements to predict total nitrogen (TN), dissolved oxygen (DO), and total phosphorus (TP) in the Yangtze River Basin, China.
View Article and Find Full Text PDFJ Vis Exp
January 2025
Department of Biomedical Engineering, Washington University in St. Louis; Department of Obstetrics & Gynecology, Washington University in St. Louis;
For noninvasive light-based physiological monitoring, optimal wavelengths of individual tissue components can be identified using absorption spectroscopy. However, because of the lack of sensitivity of hardware at longer wavelengths, absorption spectroscopy has typically been applied for wavelengths in the visible (VIS) and near-infrared (NIR) range from 400 to 1,000 nm. Hardware advancements in the short-wave infrared (SWIR) range have enabled investigators to explore wavelengths in the ~1,000 nm to 3,000 nm range in which fall characteristic absorption peaks for lipid, protein, and water.
View Article and Find Full Text PDFHardwareX
March 2025
LIGHT Community, Physics Department, Imperial College London SW7 2AZ, UK.
We recently demonstrated polarisation differential phase contrast microscopy () as a robust, low-cost single-shot implementation of (semi)quantitative phase imaging based on differential phase microscopy. utilises a polarisation-sensitive camera to simultaneously acquire four obliquely transilluminated images from which phase images mapping spatial variation of optical path difference can be calculated. microscopy can be implemented on existing or bespoke microscopes and can utilise radiation at a wide range of visible to near infrared wavelengths and so is straightforward to integrate with fluorescence microscopy.
View Article and Find Full Text PDFOpt Express
January 2025
The perceived colors of silicon-on-insulator (SOI) wafers with etched Si surface layers of thickness 90 nm to 30 nm vary from turquoise to purple to golden. Measured reflectance curves spanning ultraviolet, visible, and near infrared wavelengths have an amplitude modulated oscillatory pattern. Multilayer reflectance calculations indicate the oscillatory pattern results from the 2 µm thick buried SiO layer which functions as a nearly lossless reflective Fabry-Perot etalon in the near infrared where SiO and Si are transparent.
View Article and Find Full Text PDFPhoto-induced force microscopy (PiFM) uses laser modulation at the atomic force microscope cantilever's typical mechanical resonance frequency, to encode the material near-field response in the probes nanomechanics. While this technique offers the simplicity gained by mechanical detection, it can be challenging for hyperspectral measurements. Modulation in the visible and near-infrared ranges, often involves using acousto-optic modulators that introduce a wavelength-dependent laser steering, detrimental for spectroscopic purposes.
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