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Precise photon flux measurement of single photon sources (SPSs) is essential to the successful application of SPSs. In this work, a novel method, to our knowledge, was proposed for direct measurement of the absolute photon flux of single photon sources with a femtosecond laser multiphoton microscope. A secondary 2-mm-diameter aperture was installed under the microscope objective to define the numerical aperture (NA) of the microscope. The defined NA was precisely measured to be 0.447. An LED-based miniaturized integrating sphere light source (LED-ISLS) was used as a standard radiance source to calibrate the photon flux responsivity of the multiphoton microscope, with the defined NA. The combined standard uncertainty of the measured photon flux responsivity was 1.97%. Absolute photon flux from a quantum-dot based emitter was measured by the multiphoton microscope. The uncertainty of the photon flux was evaluated to be 2.1%. This work offers a new, to our knowledge, radiometric method for fast calibration of photon flux responsivity of microscopes, and absolute photon flux calibration of single photon sources.
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http://dx.doi.org/10.1364/OE.458745 | DOI Listing |
J Synchrotron Radiat
November 2025
State Key Laboratory of Chemical Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
This study develops an integrated X-ray absorption spectroscopy (XAS) photoemission electron microscopy (PEEM) platform on beamline BL09U at the Shanghai Synchrotron Radiation Facility (SSRF), enabling nanoscale characterization of complex materials through energy-resolved imaging and local-area XAS. By using the wide range of energy tunability, full access to different polarizations and PEEM's surface sensitivity, we have established a gap-monochromator control system under the EPICS framework to synchronize the elliptically polarized undulator (EPU) gap and monochromator energy dynamically, optimizing photon flux stability for absorption fine structure analysis. Combining X-ray magnetic circular dichroism (XMCD) and X-ray magnetic linear dichroism (XMLD) with PEEM and local-area XAS, this platform achieves concurrent mapping of electronic structures and magnetic domains in ferromagnetic nano-patterns, as demonstrated through our studies of NiFe Permalloy using this system.
View Article and Find Full Text PDFJ Org Chem
September 2025
School of Chemistry, O'Brien Centre for Science, University College Dublin, Dublin 4, Belfield D04 N2E5, Ireland.
Ynones are attractive molecular building blocks owing to their electrophilic character, which can be exploited in a variety of functionalization strategies, giving rise to valuable reaction products. This work presents a photochemical strategy for the direct generation of ynones from aldehydes and substituted alkynes bearing radicofugal groups, such as sulfones. Using TBADT (tetrabutylammonium decatungstate) as a photocatalyst, the direct photochemical synthesis of a variety of ynones is achieved in high yields and short reaction times.
View Article and Find Full Text PDFAnal Chem
September 2025
Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.
Ginseng exosomes are a kind of promising extracellular vesicle containing unique bioactive components. However, the investigation on ginseng-derived exosomes is still in the initial stage. This study developed a photonic crystal-based Bragg scattering coupling electrochemiluminescence (BSC-ECL) biosensor for detection of miRNA396a-3p in exosome-like nanoparticles (GENs) and ginseng exosomes (Gexos).
View Article and Find Full Text PDFBiology (Basel)
August 2025
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy.
L. (MA) is a member of the Moraceae family, known as "white mulberry". Due to the high levels of bioactive compounds, mulberry plants can be considered a good source of nutrients and antioxidant compounds.
View Article and Find Full Text PDFJ Phys Chem B
September 2025
James Tarpo Jr. and Margaret Tarpo Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, Indiana 47907, United States.
Raman spectroscopy is a powerful method for analyzing chemical compositions across diverse samples. Spontaneous Raman scattering (spRS) provides complete Raman spectra but typically yields low signal levels, requiring long signal integration times. In contrast, stimulated Raman scattering (SRS) produces much stronger signals, allowing for rapid spectral acquisition, and has been widely used to accelerate chemical imaging.
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