A polarization imaging device based on a femtosecond laser nanostructured birefringent array is demonstrated. The device enables instant measurement of the distribution of the Stokes vectors in the visible spectrum. Polarimetric measurements with radially and circularly polarized light distributions are demonstrated.
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http://dx.doi.org/10.1364/OL.38.004096 | DOI Listing |
Nat Commun
January 2025
The Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, PR China.
Obstructive sleep apnea is a globally prevalent concern with significant health impacts, especially when coupled with comorbidities. Accurate detection and localization of airway obstructions are crucial for effective diagnosis and treatment, which remains a challenge for traditional sleep monitoring methods. Here, we report a catheter-based flexible pressure sensor array that continuously monitors soft tissue pressure in the upper airway and facilitates at the millimeter level.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China.
Terahertz (THz) emission arising from the second-order nonlinear photocurrent effects in two-dimensional quantum materials has attracted significant attention due to its high efficiency and ease of polarization manipulation. However, in centrosymmetric quantum materials, the terahertz emission is typically suppressed, caused by the directional symmetry of the photocurrent generated under femtosecond laser excitation. In this work, we report that wafer-scale type-II Dirac semimetal PtTe with lattice centrosymmetry exhibits remarkably high THz emission efficiency (2 orders of magnitude greater than that of a ZnTe nonlinear crystal with equivalent thickness) and pronounced polarization sensitivity at room temperature.
View Article and Find Full Text PDFSci Rep
December 2024
Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132, Kassel, Germany.
The ultrafast ionic dynamics in solids induced by intense femtosecond laser excitation are controlled by two fundamentally different yet interrelated phenomena. First, the substantial generation of hot electron-hole pairs by the laser pulse modifies the interatomic bonding strength and characteristics, inducing nonthermal ionic motion. Second, incoherent electron-ion collisions facilitate thermal equilibration between electrons and ions, achieving a uniform temperature on a picosecond timescale.
View Article and Find Full Text PDFPhotochem Photobiol
December 2024
Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil.
Given that non-equilibrium molecular motion in thermal gradients is influenced by both solute and solvent, the application of spectroscopic methods that probe each component in a binary mixture can provide insights into the molecular mechanisms of thermal diffusion for a large class of systems. In the present work, we use an all-optical setup whereby near-infrared excitation of the solvent leads to a steady-state thermal gradient in solution, followed by characterization of the non-equilibrium system with electronic spectroscopy, imaging, and intensity. Using rhodamine B in water as a case study, we perform measurements as a function of solute concentration, temperature, wavelength, time, near-infrared laser power, visible excitation wavelength, and isotope effect.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Optical vortices possess a helical phase wavefront with central phase dislocation and orbital angular momentum. We demonstrated three-dimensional microstructure formation using a femtosecond optical vortex beam. Two-photon polymerization of photocurable resin was induced by long-term exposure, resulting in the fabrication of cylindrical structures.
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