Irregular and nonrepetitive transverse intensity distributions were measured in the near field during the gain-switch pulse (60-ns width) of a transversely excited atmospheric CO(2) laser. Transverse patterns are regular and repetitive in the long-pulse (1-micros width) mode and in ensemble average in the short-pulse mode, and in both cases symmetry is imposed by the boundary conditions. Short-pulse transverse patterns formed by lasing domains appear with a mean size of 0.8 mm. The prediction of domain size based on a model of population inversion filamentation agrees with the experimental result.
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http://dx.doi.org/10.1364/ol.21.001153 | DOI Listing |
Sci Rep
March 2025
School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK.
We demonstrate a methane gas imaging system mounted to an unmanned aerial vehicle (UAV) that is shown to perform real-time detection at distances up to 10m whist airborne. Laser diodes that switch between on- and off- resonance with a methane absorption line are used to flood-illuminate a scene. The scene is imaged with an infrared InGaAs camera and the differential of the on-resonance and off-resonance back-scatter images are used to reveal the gas distribution.
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March 2025
Laboratory of Materials, Signals, Systems and Physical Modeling, Faculty of Science, University Ibn Zohr, Agadir, Morocco.
This study explores the development of highly sensitive hydrogen sulfide (HS) gas sensors employing hierarchical aluminum-doped zinc oxide (AZO) nanostructures. Vertically oriented AZO nanoplatelets with Al/ZnO molar ratios of 4% and 6% were successfully synthesized using an automated successive ionic layer adsorption and reaction (SILAR) technique. The morphological features of the AZO films significantly changed with the Al content.
View Article and Find Full Text PDFNat Commun
March 2025
Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France.
Understanding how a system's behavior extrapolates beyond 3D is a fundamental question in physics, spanning topics from unification theories to critical phenomena. In statistical physics, fluctuations' strength is highly sensitive to dimensionality, affecting phase transitions. In low dimensions, phase transitions are suppressed, while high-dimensional systems exhibit simpler mean-field behavior.
View Article and Find Full Text PDFJ Am Chem Soc
March 2025
Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou 310030, Zhejiang, China.
Reducing the formation overpotential of key reaction intermediates represents a major challenge in developing broad electrocatalytic reactions. Recent vibrational spectroscopic studies of electrochemical CO or CO reduction reaction (CORR) characterized an interesting formation of stochastic CO (CO) intermediate with negligible energy losses under certain circumstances. Yet, the precise formation conditions and mechanisms remain unclear, hindering the correct understanding of related spectroscopic results and utilization of these effects to develop the CORR and other electrocatalytic reactions.
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February 2025
Programa de Doctorado de Ciencias Agroalimentarias, Facultad de Ciencias Agronómicas y de los Alimentos, Pontifica Universidad Católica de Valparaíso, Valparaíso 2340000, Chile.
The increasing demand for functional foods with added health benefits has driven the development of innovative food products. This study aimed to develop a functional snack made from Granny Smith apples enriched with hydrolyzed collagen using impregnation technologies, including vacuum impregnation (VI), ultrasound (US), and moderate electric field (MEF), and pretreatment with CO laser microperforations (MPs) combined with drying methods, including conventional drying (CD) and refractance window drying (RW). The collagen content increased significantly across treatments, with MP-I achieving the highest retention (79.
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