Stimulated Raman side scattering of an ultrashort high power laser pulse is studied in experiments on laser wakefield acceleration. Experiments and simulations reveal that stimulated Raman side scattering occurs at the beginning of the interaction, that it contributes to the evolution of the pulse prior to wakefield formation, and also that it affects the quality of electron beams generated. The relativistic shift of the plasma frequency is measured.
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http://dx.doi.org/10.1103/PhysRevLett.105.034801 | DOI Listing |
Nat Methods
January 2025
Department of Electrical and Computer Engineering, Boston University, Boston, MA, USA.
Super-resolution imaging of cell metabolism is hindered by the incompatibility of small metabolites with fluorescent dyes and the limited resolution of imaging mass spectrometry. We present ultrasensitive reweighted visible stimulated Raman scattering (URV-SRS), a label-free vibrational imaging technique for multiplexed nanoscopy of intracellular metabolites. We developed a visible SRS microscope with extensive pulse chirping to improve the detection limit to ~4,000 molecules and introduced a self-supervised multi-agent denoiser to suppress non-independent noise in SRS by over 7.
View Article and Find Full Text PDFIn this study, we investigated in detail the regulation mechanism of electron transfer under laser-induced breakdown (LIB) on weak O-D stimulated Raman scattering (SRS) in DMSO-DO solutions. Significantly, the Raman activity of O-D vibrations was greatly enhanced by two orders of magnitude due to electron transfer in DMSO molecules. Density functional theory (DFT) calculations showed that the O-D Raman activity was significantly enhanced in the DMSO-DO dimer compared to the DO dimer.
View Article and Find Full Text PDFWe introduce and characterize a fast (50 kHz), long range (50 ps) and random-access optical delay line based on an acousto-optic deflector inserted in the Fourier plane of a zero-dispersion line. The advantages of this agile delay line are demonstrated in the context of impulsive stimulated Raman imaging in the low-frequency range (<200 cm). Besides fast imaging with a spectral resolution of 1.
View Article and Find Full Text PDFThis publisher's note contains a correction to Opt. Lett.49, 4863 (2024)10.
View Article and Find Full Text PDFAnal Chem
January 2025
Guangdong Key Laboratory of Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen University, Shenzhen 518060, PR China.
Accompanying the occurrence of inflammatory reaction to release cytokines, pyroptosis can activate an immune response for resistance against cancer. Consequently, elevated levels of cytokines released by cancer cells are highly correlated with the effectiveness of cancer treatment. Herein, a noninvasive surface-enhanced Raman spectroscopy (SERS) immunosensor was developed to sensitively and specifically measure the tumor necrosis factor-α (TNF-α), a proinflammatory cytokine, during the cell pyroptosis process.
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