نتایج جستجو برای: cherenkov radiation
تعداد نتایج: 239940 فیلتر نتایج به سال:
We discuss the Cherenkov process ν → νγ in the presence of a homogeneous magnetic field. The neutrinos are taken to be massless with only standard-model couplings. The magnetic field fulfills the dual purpose of inducing an effective neutrino-photon vertex and of modifying the photon dispersion relation such that the Cherenkov condition ω < |k| is fulfilled. For a field strength Bcrit = m 2 e/e...
An example of discontinuity of the energy-momentum tensor moving at superluminal velocity is discussed. It is shown that the gravita-tional Mach cone is formed. The power spectrum of the corresponding Cherenkov radiation is evaluated.
Measurements of Cherenkov emission in tissue during radiation therapy are shown to enable estimation of hemoglobin oxygen saturation non-invasively, through spectral fitting of the spontaneous emissions from the treated tissue. Tissue oxygenation plays a critical role in the efficacy of radiation therapy to kill tumor tissue. Yet in-vivo measurement of this has remained elusive in routine use b...
Spectrally-isolated narrowband Cherenkov radiation from commercial nonlinear photonic crystal fibers is demonstrated as an ultrafast optical source with a visible tuning range of 485-690 nm, which complementarily extends the near-infrared tuning range of 690-1020 nm from the corresponding femtosecond Ti:sapphire pump laser. Pump-tosignal conversion efficiency routinely surpasses 10%, enabling m...
We review the recent developments in the field of ultrafast Cherenkov fiber lasers. Two essential properties of such laser systems - broad wavelength tunability and high efficiency of Cherenkov radiation wavelength conversion are discussed. The exceptional performance of the Cherenkov fiber laser systems are highlighted - dependent on the realization scheme, the Cherenkov lasers can generate th...
We reported a record high power (>250 mW) and compact near-infrared fiber-optic femtosecond Cherenkov radiation source and its new application on nonlinear light microscopy for the first time (to our best knowledge). The high power femtosecond Cherenkov radiation was generated by 1.03 μm femtosecond pulses from a portable diode-pumped laser and a photonic crystal fiber as a compact, flexible, a...
Cherenkov radiation may occur whenever the source is moving faster than waves it generates. In a dominated universe, with equation-of-state $w = 1/3$, we have recently shown that Bardeen scalar-metric perturbations contribute to linearized Weyl tensor in such manner its wavefront propagates at acoustic speed $\sqrt{w}=1/\sqrt{3}$. this work, explicitly compute shape of cone and wedge generated ...
In this paper, relativistic Cherenkov radiation was studied in a 3-D magneto-dielectric medium. Electric permittivity and magnetic permeability of the medium as functions of frequency, are assumed to satisfy Kramers- Kronig equations. A new interaction Hamiltonian, which is different from Hamiltonian term in non-relativistic state, was introduced by the quantized vector potential field and part...
Charged particles traveling through a conventional medium at a speed greater than the speed of light in the medium produce Cherenkov radiation in the forward directions, which is useful for particle identification and counting. Newly designed metamaterial, with their negative index of refraction, flips the radiated photons backward and thus readily separates the radiation from the emitting part...
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