Images of mammalian organs were built up using a Laser collimated transillumination device equipped with a bidirectional scanning setup. A microcomputer was used to run the scanning process, acquisition of detected signals and images restitution. The images featured a satisfactory resolution of optical discontinuities on both sample surfaces. Light scattering within biological tissues restricted the spatial discrimination encountered with geometrical selection approach. By combining space and time resolution at various wavelengths, the production of an efficient tomospectroscopy could be envisaged.
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http://dx.doi.org/10.1016/0141-5425(84)90013-x | DOI Listing |
Phys Rev Lett
December 2024
Stanford University, Department of Mechanical Engineering, Stanford, California 94305, USA.
The extreme electric fields created in high-intensity laser-plasma interactions could generate energetic ions far more compactly than traditional accelerators. Despite this promise, laser-plasma accelerator experiments have been limited to maximum ion energies of ∼100 MeV/nucleon. The central challenge is the low charge-to-mass ratio of ions, which has precluded one of the most successful approaches used for electrons: laser wakefield acceleration.
View Article and Find Full Text PDFThis work investigates how misalignments of collimation lenses affect two performance criteria: minimum throughput within an angular window and maximum beam height. Based on these criteria, we establish an alignment concept for the first section of a LiDAR emitter. The performance criteria are derived from the overall LiDAR system requirements and applied to an optical system consisting of a laser diode array source, a microlens array for slow-axis collimation, and an acylinder for fast-axis collimation.
View Article and Find Full Text PDFNat Commun
January 2025
School of Mathematics and Physics, Queen's University Belfast, Belfast, UK.
Laser-plasma acceleration of protons offers a compact, ultra-fast alternative to conventional acceleration techniques, and is being widely pursued for potential applications in medicine, industry and fundamental science. Creating a stable, collimated beam of protons at high repetition rates presents a key challenge. Here, we demonstrate the generation of multi-MeV proton beams from a fast-replenishing ambient-temperature liquid sheet.
View Article and Find Full Text PDFNanophotonics
January 2025
College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou, Guangdong 510632, China.
Grating under auto-collimation configuration with polarization-independent high diffraction efficiency plays an important role in the displacement measurement system, spectral beam combining system and so on. In this paper, we proposed, for the first time, a reflective two-dimensional metal-dielectric grating of which the (-1, -1) order beam is diffracted back along the input light direction, when the incident azimuth angle is 45°. With optimized structure, the (-1, -1) order diffraction efficiencies of transverse electric polarization (TE) and transverse magnetic polarization (TM) are 95.
View Article and Find Full Text PDFEur J Radiol
January 2025
Department of Stereotactic and Functional Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, 79106 Freiburg, Germany; Fraunhofer Institute for Laser Technology (ILT), 52074 Aachen, Germany.
Purpose: Directional deep brain stimulation (dDBS) relies on electrodes steering the stimulation field in a specific direction. Post implantation, however, the intended and real orientation of the lead frequently deviates e.g.
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