A Femtosecond Electron Diffraction Device Accelerated by Terahertz Driven Electron Pulses

Abstract

The invention relates to a terahertz-driven electronic pulse accelerating femtosecond electron diffraction device which comprises a femtosecond laser, a beam splitter, an ultraviolet laser pulse generator, a terahertz pulse generator, an electron gun, an electron focusing device, a sample room, an imaging device and a camera. After the femtosecond laser emitted by the femtosecond laser passes through the beam splitter, one beam of femtosecond laser enters the ultraviolet laser pulse generator, and the other beam of femtosecond laser enters the terahertz pulse generator through a mirror. An ultraviolet laser pulse and a terahertz pulse received by the electron gun enter the cavity of the electron gun to produce an electronic pulse. The electron focusing device is mounted between the cavity of the electron gun and the sample room. A sample assembly and the imaging device are placed inside the sample room in sequence along the emitting direction of the electronic pulse. The camera is placed at a position, facing the imaging device directly, outside the sample room. The device can run in a reflection or transmission mode, can be used in research of both a reversible process and an irreversible process, and is of high brightness and high spatial-temporal resolution.

Description

technical field [0001] The invention belongs to the technical field of time-resolved electron diffraction, and in particular relates to a femtosecond electron diffraction device for terahertz-driven electron pulse acceleration. Background technique [0002] Electrons have been continuously researched and applied by scientists since they were discovered by J.J. Thomson experiment in 1897. In 1924, de Broglie predicted that moving electrons also have wave properties, and their wavelength is λ=h / mv. Just three years later (1927), two studies were completed by G.P. Thomson and C.J. Davidson-L.H. Germer respectively. Three independent electron diffraction experiments have confirmed the wave nature of electrons (milestone nodes), which laid the foundation for the use of electrons to probe the structure of matter. Since then, electrons have appeared on the historical stage in the form of probes. With the help of the femtosecond laser in the 1980s, Williamson et al. completed the ...

AI Technical Summary

Problems solved by technology

However, similar to the RF compression femtosecond electron diffraction device, the time resolution of the traditional MeV femtosecond electron diffraction device is severely limited by the time jitter between the pump laser and the probe electron, which is about 130fs

At the same time, due to the high energy of electrons, it may cause damage to the sample

In addition, the device involves accelerator-related technologies, with complex structure, huge volume and high cost

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