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We demonstrate a wavelength tunable optical excitation source for coherent Raman scattering (CRS) spectroscopy based on a single femtosecond fiber laser. Electrically controlled wavelength tuning of Stokes optical pulses was achieved with soliton self frequency shift in an optical fiber, and linear frequency chirping was applied to both the pump and the Stokes waves to significantly improve the spectral resolution. The coherent anti-Stokes Raman scattering (CARS) spectrum of cyclohexane was measured and vibrational resonant Raman peaks separated by 70 cm(-1) were clearly resolved. Single laser-based tunable excitation may greatly simplify CRS measurements and extend the practicality of CRS microscopy.
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http://dx.doi.org/10.1063/1.3657529 | DOI Listing |
Acc Chem Res
September 2025
Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke Street W, Montréal, Québec H3A 0B8, Canada.
ConspectusMolecular photochemistry, by harnessing the excited states of organic molecules, provides a platform fundamentally distinct from thermochemistry for generating reactive open-shell or spin-active species under mild conditions. Among its diverse applications, the resurgence of the Minisci-type reaction, a transformation historically reliant on thermally initiated radical conditions, has been fueled by modern photochemical strategies with improved efficiency and selectivity. Consequently, the photochemical Minisci-type reaction ranks among the most enabling methods for C()-H functionalizations of heteroarenes, which are of particular significance in medicinal chemistry for the rapid diversification of bioactive scaffolds.
View Article and Find Full Text PDFPLoS One
September 2025
The School of Electrics and Information Engineering, Yunnan Minzu University, Kunming, China.
To address the growing demand for compact and high-performance microwave filters in modern communication systems, a mixed-mode bandpass filter is proposed in the article. A dual-layer substrate integrated waveguide resonator loaded with a capacitive patch (CP-DSIWR) is proposed and theoretically analyzed, with both patch modes and cavity modes existing. To construct the bandpass filter, two rows of metallic vias are designed in the CP-SIWR to enable coupling between the two types of the modes, with the structure being fed by microstrip line.
View Article and Find Full Text PDFLab Chip
September 2025
Department of Biomedical Engineering, Lund University, Lund, Sweden.
Droplet splitting plays an important role in droplet microfluidics by providing precise control over droplet size, which is essential for applications such as single-cell analysis, biochemical reactions, and the fabrication of micro- and nanosized material. Conventional methods of droplet splitting using obstructions or junctions in the microchannel have a clear limitation that the split ratio for a particular device remains fixed, while existing active splitting methods are constrained by low flow rates, the need for complex systems, or limitations to specific droplet types. In this study, we demonstrate that droplet splitting can be achieved simply using a one-dimensional standing-wave field excited within a microchannel.
View Article and Find Full Text PDFSmall
September 2025
Department of Applied Biology and Chemical Technology and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hong Kong, 999077, P. R. China.
The precise modulation of the lifetime and the responsive properties of room-temperature phosphorescence (RTP) is essential for realizing its multifunctional applications. Herein, a facile strategy is presented to achieve a series of cellulose benzoate esters (CBE-X, X = H/CH/OH/NH) with lifetime-tunable RTP through substituent engineering. Enhancing the electron-donating ability of CBE-X effectively modulates the HOMO-LUMO gap, exciton energy, spin-orbit coupling, and interaction between cellulose chains, thereby enabling control over the RTP lifetime.
View Article and Find Full Text PDFCommun Biol
September 2025
Chemical Engineering, IIT, Gandhinagar, Gujarat, India.
Fluorescent molecules are essential for bioimaging and visualizing cellular localization, functionalities, including biosensing, ion sensing, and photochromism. The photocleavable fluorescent protein PhoCl1 belongs to a sub-class of green-to-red photoconvertible β-barrel fluorescent protein and has a characteristic green fluorescence conferred by the chromophore p-HBI. In contrast to other photoconvertible proteins, that shift their fluorescence from green-to-red upon photoexposure, PhoCl1 has been reported to render itself non-fluorescent by releasing the 9 amino-acid C-terminal peptide fragment (CTPF) bearing the photo-transformed red chromophore from the β-barrel.
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