An integrated arrayed-waveguide grating fabricated in silicon-oxynitride technology is applied to Raman spectroscopy. After its validation by reproducing the well-known spectrum of cyclohexane, polarized Raman spectra are measured of extracted human teeth containing localized initial carious lesions. Excellent agreement is obtained between the spectra of healthy and carious tooth enamel measured with our integrated device and spectra recorded using a conventional Raman spectrometer. Our results represent a step toward the realization of compact, hand-held, integrated spectrometers, e.g. for the detection of dental caries at an early stage.
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http://dx.doi.org/10.1364/OL.36.004629 | DOI Listing |
Environ Sci Technol
January 2025
School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853, United States.
Phosphorus recovery through enhanced biological phosphorus removal (EBPR) processes from agricultural wastes holds promise in mitigating the impending global P shortage. However, the complex nutrient forms and the microbial augments, expected to exert a profound impact on crop rhizomicrobiome and thus crop health, remained unexplored. In this study, we investigated the impacts of EBPR biosolids on crops growth and rhizomicrobiome in comparison to chemical fertilizer and Vermont manure compost.
View Article and Find Full Text PDFNanotoxicology
January 2025
Institute of Physics Belgrade, University of Belgrade, Belgrade, Serbia.
In this study, we investigated the cytotoxic effect of highly soluble dextran-coated CeO nanoparticles on human fetal lung fibroblasts MRC-5. We examined individual nanoparticle-treated cells by Raman spectroscopy and analyzed Raman spectra using non-negative principal component analysis and k-means clustering. In this way, we determined dose-dependent differences between treated cells, which were reflected through the intensity change of lipid, phospholipid and RNA-related Raman modes.
View Article and Find Full Text PDFNanophotonics
January 2025
Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.
A combination of femtosecond stimulated Raman scattering and surface-enhanced Raman scattering, termed surface-enhanced stimulated Raman scattering (SE-FSRS), was proposed to leverage both temporal precision and sensitivity for advanced molecular dynamics analysis. During the initial successful implementations of this approach, unexpected spectral distortions were observed, and several potential explanations were proposed. Further progress in this novel technique and its broader implementation requires a profound understanding of the factors influencing the shape of the registered spectra and the underlying mechanisms.
View Article and Find Full Text PDFNanophotonics
January 2025
Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Sum-frequency generation (SFG) enables the coherent upconversion of electromagnetic signals and plays a significant role in mid-infrared vibrational spectroscopy for molecular analysis. Recent research indicates that plasmonic nanocavities, which confine light to extremely small volumes, can facilitate the detection of vibrational SFG signals from individual molecules by leveraging surface-enhanced Raman scattering combined with mid-infrared laser excitation. In this article, we compute the degree of second order coherence ( (0)) of the upconverted mid-infrared field under realistic parameters and accounting for the anharmonic potential that characterizes vibrational modes of individual molecules.
View Article and Find Full Text PDFACS Catal
January 2025
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Partial oxidation of ethylene over silver catalysts produces more than 30 million metric tons of ethylene oxide (EO) annually. However, the form of active silver surfaces, reactive oxygen species, and dominant pathways of this chemical reaction remains controversial despite decades of research. Here, we use Raman spectroscopy and transient kinetic measurements to demonstrate that higher coverages of peroxide species, present only upon Ag oxide surfaces that form , correlate with greater selectivities to EO.
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