Bunch Length Measurement Employing Cherenkov Radiation from a Thin Silica Aerogel

Nanbu, Kenichi; Saito, Yuki; Saito, Hirotoshi; Kashiwagi, Shigeru; Hinode, F.; Muto, T.; Hama, Hiromitsu

doi:10.3390/particles1010025

Cited by 6 publications

(2 citation statements)

References 14 publications

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“…CR is characterized by a directional, polarized, cone-shaped radiation pattern with opening semi-angle θ c satisfying cos θ c = 1/β n (ω), where β = v / c is the speed of the particles normalized by the speed of light and n (ω) is the refractive index of the medium. We assume that the emission is detected with a far-field detector located at a specific azimuthal angle on the cone’s rim, providing broadband detection of all frequency components [note that in certain practical situations, the entire emission ring (over all azimuthal angles) could be collected using special optics ( 54 )—thereby increasing the signal level]. Using the far-field expression for the dyadic Green tensor of a uniform dielectric medium ( 52 ),

, and assuming weak material dispersion, we find from Eqs.…”

Section: Resultsmentioning

confidence: 99%

The coherence of light is fundamentally tied to the quantum coherence of the emitting particle

et al. 2021

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Coherent emission of light by free charged particles is believed to be successfully captured by classical electromagnetism in all experimental settings. However, recent advances triggered fundamental questions regarding the role of the particle wave function in these processes. Here, we find that even in seemingly classical experimental regimes, light emission is fundamentally tied to the quantum coherence and correlations of the emitting particle. We use quantum electrodynamics to show how the particle’s momentum uncertainty determines the optical coherence of the emitted light. We find that the temporal duration of Cherenkov radiation, envisioned for almost a century as a shock wave of light, is limited by underlying entanglement between the particle and light. Our findings enable new capabilities in electron microscopy for measuring quantum correlations of shaped electrons. Last, we propose new Cherenkov detection schemes, whereby measuring spectral photon autocorrelations can unveil the wave function structure of any charged high-energy particle.

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, and assuming weak material dispersion, we find from Eqs.…”

Section: Resultsmentioning

confidence: 99%

The coherence of light is fundamentally tied to the quantum coherence of the emitting particle

et al. 2021

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“…It means that there are no distortions of experimental results in comparison with the case when the fiber is inclined at the Cherenkov angle. In, 15) a bunch length of approximately 250 fs was measured using a streak camera.…”

Section: Introductionmentioning

confidence: 99%

Cherenkov radiation and cathodoluminescence in sapphire, quartz, and diamond under the excitation of an electron beam

Тарасенко¹,

Бакшт²,

Белоплотов³

et al. 2020

Jpn. J. Appl. Phys.

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The paper reports data on the emission of sapphire, KU-1 quartz, and synthetic diamond in the wavelength range of 200–800 nm excited by a pulsed electron beam with an energy of up to 350 keV. Broadband radiation, the intensity of which increases with decreasing wavelength in the range of 220–400 nm, was detected. Such dependence of the radiation intensity on the wavelength is characteristic of Cherenkov radiation (CR). Moreover, the duration of the radiation pulse coincides with that of the electron beam current pulse. For sapphire and quartz, the duration of radiation pulses at the spectral range 220–400 nm is close to the duration to electron beam current pulses. For synthetic diamonds, both cathodoluminescence and CR are detected in this spectral region. The intense band of free excitons with maximum at 235 nm is found at high beam current densities and electron energies 50–350 keV.

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Comment on “Nonlinear quantum effects in electromagnetic radiation of a vortex electron”

et al. 2022

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This comment on the Phys. Rev. A paper "Nonlinear quantum effects in electromagnetic radiation of a vortex electron" by Karlovets and Pupasov-Maximov [Phys. Rev. A 103, 12214 (2021)] addresses their criticism of the combined experimental and theoretical study "Observing the quantum wave nature of free electrons through spontaneous emission" by Remez et al, published in Phys. Rev. Lett. [Phys. Rev. Lett. 123, 060401 (2019)]. We show, by means of simple optical arguments as well as numerical simulations, that the criticism raised by Karlovets and Pupasov-Maximov regarding the experimental regime reported by Remez et al is false. Further, we discuss a necessary clarification for the theoretical derivations presented by Karlovets and Pupasov-Maximov, as they only hold for a certain experimental situation where the final state of the emitting electron is observed in coincidence with the emitted photon -which is not the common scenario in cathodoluminescence. Upon lifting the concerns regarding the experimental regime reported by Remez et al, and explicitly clarifying the electron post-selection, we believe that the paper by Karlovets and Pupasov-Maximov may constitute a valuable contribution to the problem of spontaneous emission by shaped electron wavefunctions, as it presents new expressions for the emission rates beyond the ubiquitous paraxial approximation.

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Bunch Length Measurement Employing Cherenkov Radiation from a Thin Silica Aerogel

Cited by 6 publications

References 14 publications

The coherence of light is fundamentally tied to the quantum coherence of the emitting particle

The coherence of light is fundamentally tied to the quantum coherence of the emitting particle

Cherenkov radiation and cathodoluminescence in sapphire, quartz, and diamond under the excitation of an electron beam

Comment on “Nonlinear quantum effects in electromagnetic radiation of a vortex electron”

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