A proof-of-principle experiment demonstrates the generation of radiation from the Cherenkov wake excited by an ultrashort- and ultrahigh-power pulse laser in a perpendicularly magnetized plasma. The frequency of the radiation is in the millimeter range (up to 200 GHz). The intensity of the radiation is proportional to the magnetic field intensity as expected by theory. Polarization of the emitted radiation is also detected. The difference in the frequency of the emitted radiation between these experiments and previous theory can be explained by the electrons' oscillation in the electric field of a narrow column of ions in the focal region.
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http://dx.doi.org/10.1103/PhysRevLett.89.065003 | DOI Listing |
Adv Sci (Weinh)
January 2025
Key Laboratory of Ocean Observation‑Imaging Testbed of Zhejiang Province, Ocean College, Zhejiang University, Hangzhou, 310058, China.
Cherenkov radiation (CR) is a fascinating phenomenon that occurs not only in electromagnetic (EM) waves but also in water waves. The V-shaped wake formed by a moving object on the water surface results from the constructive interference of water waves of different wavelengths, similar to CR. We designed and fabricated a one-dimensional (1D) water wave crystal to analogize the behavior of moving particles in water waves.
View Article and Find Full Text PDFWe demonstrate experimentally an efficient terahertz emitter that consists of a 20 µm thick layer of LiNbO clamped between a fused silica substrate and a Si semicone. A focused laser beam from an ultrafast optical oscillator propagates in the LiNbO layer and emits a Cherenkov cone of terahertz radiation to the Si semicone. The radiation is totally internally reflected by the semicone's convex surface and escapes the semicone through its base as a collimated beam.
View Article and Find Full Text PDFProc SPIE Int Soc Opt Eng
February 2024
Radiation Monitoring Devices, Inc., 44 Hunt St., Watertown, MA, USA 02472- 4624.
Development of new scintillator materials is a continuous effort, which recently has been focused on materials with higher stopping power. Higher stopping power can be achieved if the compositions include elements such as Tl (Z=81) or Lu (Z=71), as the compounds gain higher densities and effective atomic numbers. In context of medical imaging this translates into high detection efficiency (count rates), therefore, better image quality (statistics, thinner films) or lower irradiation doses to patients in addition to lowering of cost.
View Article and Find Full Text PDFBiomed Phys Eng Express
December 2024
School of Health Sciences, Department of Radiological Technology, Nagoya University, Japan.
Cherenkov radiation is emitted during x-ray irradiation in a linear accelerator (LINAC). Cherenkov light contains many short wavelength components, including ultraviolet (UV) light, which is well-known for its bactericidal effects. A similar phenomenon is probable for human cancer cells.
View Article and Find Full Text PDFVortex free-electron radiation has attracted considerable interest because of its promising potential for applications in communication, high-density radiation sources, and particle detection. Here, we reveal angular momentum modulation of vortex Cherenkov radiation using subwavelength silicon waveguides. The topological charge of vortex radiation field can be controlled by the position parameters of two electron beams based on the rotational symmetry.
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