相关论文: Permanent Magnets Undulator for Terahertz FEL
A simple analysis is given for optimum length of undulator in self-seeding free electron laser (FEL). The obtained relations show the correlation between the undulator length and the system parameters. The power required for the seeding in…
We describe the design, assembly, and testing of a magnet intended to deflect beams of paramagnetic nanoclusters, molecules, and atoms. It is energized by high-grade permanent neodymium magnets. This offers a convenient option in terms of…
Both theoretical and numerical analyses are conducted to investigate terahertz (THz) radiation emission from free-electron lasers. The angular and spectral characteristics of radiation are analytically evaluated leveraging Linenard Wiechert…
We report a Mueller matrix ellipsometer design using dual continuously rotating anisotropic meta wave plates which determines the full set of Mueller matrix elements in the terahertz spectral range. The instrument operates in the frequency…
A permanent magnet assembly in which the flux density can be altered by a mechanical operation is often significantly smaller than comparable electromagnets and also requires no electrical power to operate. In this paper five permanent…
We present a laboratory electromagnet capable of generating magnetic fields up to $\pm$0.48T, specifically designed as a perpendicular flux source for thin film samples in an ambient environment. The magnet features a 250mm diameter clear…
We show that radiation pulses from an X-ray Free-Electron Laser (XFEL) with a planar undulator, which are mainly polarized in the horizontal direction, exhibit a suppression of the vertical polarization component of the power at least by a…
Ultrarelativistic charged particles are predicted to emit hard electromagnetic radiation of undulator type while being channeled in a crystal with periodically bent crystallographic planes. The recently proposed crystalline undulator with…
We re-examine the nature of the turbulent magnetic diffusivity tensor of mean field electrodynamics and show that an inconsistency arises if it is calculated via consideration of time-independent magnetic fields. Specifically, the predicted…
In this paper we discuss the design choices and construction strategy of the tapered undulator system designed for a high energy extraction efficiency experiment in the ultraviolet region of the electromagnetic spectrum planned for…
We review the theory of FEL oscillators operating with tapered undulators. We consider the case of a uniform tapering and introduce a parameter which characterizes the effect of the tapering on the gain and on the saturation intensity. We…
We describe the construction of a prototype hybrid permanent magnet dipole and quadruple. The magnet consists of two concentric rings of SmCo magnetic material 5 cm in length. The outer ring is made of 16 uniformly magnetized blocks…
Free-electron lasers (FELs) over virtually the entire electromagnetic spectrum from microwaves through ultraviolet through hard x-rays that are either seeded or start from noise. FELs can produce a variety of different optical polarizations…
The undulator is a critical component to produce synchrotron radiation and free electron laser. When a Bessel light beam carrying the orbit angular momentum co-propagates with an electron beam, a net transverse deflection force will be…
We describe a future possible upgrade of the European XFEL consisting in the construction of an undulator beamline dedicated to life science experiments. The availability of free undulator tunnels at the European XFEL facility offers a…
The magnetic gap of the baseline XFEL undulators can be varied mechanically for wavelength tuning. In particular, the wavelength range 0.1 nm - 0.4 nm can be covered by operating the European XFEL with the SASE2 undulator. The length of the…
We report on generation of pulsed broadband terahertz radiation utilizing the inverse spin Hall effect in Fe/Pt bilayers on MgO and sapphire substrates. The emitter was optimized with respect to layer thickness, growth parameters,…
Using the Hubbard model Hamiltonian in a mean field level, we examine the variation of antiferromagnetic strength with applied magnetic field. It is demonstrated that minima in the antiferromagnetic strength exist at the the even integer…
Terahertz spintronics offers the prospect of devices which are both faster and more energy-efficient. A promising route to achieve this goal is to exploit current-induced spin-orbit torques. However, the high-frequency properties of these…
A design for a permanent magnet system is proposed that generates spatially homogeneous, constant magnetic field gradients, thus creating conditions suitable for MRI without gradient coils and amplifiers. This is achieved by superimposing a…