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Ruixuan Huang

Bio: Ruixuan Huang is an academic researcher from University of Science and Technology of China. The author has contributed to research in topics: Terahertz radiation & Thermal emittance. The author has an hindex of 3, co-authored 14 publications receiving 27 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a train of laser pulses with THz repetition rate is used to drive a photocathode direct current (DC) gun, leading to the emission of electron bunches, which is subsequently accelerated by the gun field and applied to selectively excite one of the modes in the dielectric loaded waveguide (DLW) structure.
Abstract: We propose a novel scheme to generate a tunable narrow-band THz radiation. In this scheme, a train of laser pulses with THz repetition rate is used to drive a photocathode direct current (DC) gun, leading to the emission of a train of electron bunches. The electron bunch train is subsequently accelerated by the gun field and applied to selectively excite one of the modes in the dielectric loaded waveguide (DLW) structure, which is located downstream the DC gun. Thanks to the tunability of the repetition rate of laser pulses and the gun voltage, a tunable narrow-band THz radiation source can be obtained. This proposed source has the advantages of compactness, robustness and relatively high power.

9 citations

Journal ArticleDOI
19 Nov 2018
TL;DR: In this article, a pre-bunched free electron laser (FEL) was used to investigate the collective behavior of electron dynamics, and the authors proposed a new high throughput material characterization system, which supplies a multiple light source.
Abstract: Terahertz (THz) radiation has attracted much attention in new scientific and industrial applications. There has been significant recent progress in generating THz with accelerators. To investigate the collective behavior of electron dynamics, we have proposed a new high throughput material characterization system, which supplies a multiple light source. The system includes a pre-bunched THz free electron laser (FEL), which is a high-power narrow-band THz source with a wide tuning range of frequency. The physical design with the main components of the facility is introduced, and the simulation results are illustrated. Radiation of 0.5–3.0 THz is obtained by the fundamental wave of the pre-bunched beam, and radiation covering 3.0–5.0 THz is realized by second harmonic generation. As the simulation shows, intense THz radiation could be achieved in a frequency from 0.5–5.0 THz, with a peak power of several megawatts (MWs) and a bandwidth of a few percent.

5 citations

Patent
23 Jan 2018
TL;DR: In this article, a high-power terahertz free electron laser radiation source is presented, which includes an electron gun, a solenoid coil, a mirror, a laser pulse train, a traveling wave accelerating tube,a power divider, a power source, a phase shifter and attenuator, and an undulator.
Abstract: The invention discloses a high-power terahertz free electron laser radiation source which includes an electron gun, a solenoid coil, a mirror, a laser pulse train, a traveling wave accelerating tube,a power divider, a power source, a phase shifter and attenuator, and an undulator. The laser pulse train irradiates the cathode material of the photocathode microwave electron gun through the mirror to generate an electronic pulse train. After being accelerated by the microwave electric field in the electron gun and focused by the magnetic field of the solenoid coil, the electronic pulse train enters the traveling wave accelerating tube to make compensation for energy dispersion, in order to reduce the high-power terahertz radiation generated by the electronic pulse train after energy dispersion in the undulator. The power source allocates microwave power for the electron gun and the traveling wave accelerating tube through the power divider according to a specific proportion. The amplitude and phase of the microwave electric field in the travelling wave accelerating tube are adjusted by the phase shifter and attenuator, so that a maximum terahertz radiation power is obtained as an optimization goal. The high-power terahertz free electron laser radiation source has high radiation power. The power of terahertz radiation is greatly improved by reducing the energy dispersion of the electronic pulse train. The high-power terahertz free electron laser radiation source has a compact structure, and is easy to implement in technology.

4 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a new type of dielectric loaded waveguide structure named separated Dielectric Loaded Waveguide (SDLW), whose dielectrics layer and metal layer are separated with each other.
Abstract: In this paper, we propose a new type of dielectric loaded waveguide structure named separated dielectric loaded waveguide (SDLW), whose dielectric layer and metal layer are separated with each other. The characters of wakefield inside SDLW are studied in details by theory analysis and numerical simulation. Compared with the ordinary dielectric loaded waveguide, the peak power of Terahertz coherent Cherenkov radiation (CCR) excited by the short relativistic electron bunch can be enhanced by over one order. Therefore, this new structure offers a promising candidate for high power THz source.

3 citations

Journal ArticleDOI
TL;DR: In this article, a brake-applied velocity bunching scheme is proposed, in which the electron bunch is injected into the accelerator with a low gradient at a deceleration phase, like "a brake is applied" and afterward slips to an acceleration phase.
Abstract: Velocity bunching technique is a tool for compressing electron beams in modern high brightness photoinjector sources, which utilizes the velocity difference introduced by a traveling rf wave at a relatively low energy. It presents peculiar challenges when applied to obtain a beam with a very high current and a low transverse emittance in photoinjectors. The main difficulty is to control the emittance oscillations of the beam during high compression, which can be naturally considered as an extension of the emittance compensation process. In this paper, a brake-applied velocity bunching scheme is proposed, in which the electron bunch is injected into the accelerator with a low gradient at a deceleration phase, like “a brake is applied”, afterward slips to an acceleration phase. During the entire compression process, the energy chirp induced by the rf field is mostly linear, which retains a symmetric electron beam in the temporal distribution. The key point of the new scheme is a smaller energy chirp at a lower beam energy compared with the normal velocity bunching. Besides, the beam energy chirp before compression is dominated by the linear correlation due to a relatively short laser pulse. With a symmetric bunch compression, the transverse emittance could be compensated even if the compression factor is extremely high. As to our simulation results, the peak current of the compressed beam can be above 1.8 kA for the charge of 800 pC with a good emittance compensation.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the spectral distribution of Cherenkov radiation in the interior of a dielectric cylinder is studied for three types of radiation: (i) CHNE in the exterior medium, (ii) radiation on the guided modes of the cylinder, and (iii) emission of surface polaritons.
Abstract: We investigate the radiation from a charged particle moving outside a dielectric cylinder parallel to its axis. It is assumed that the cylinder is immersed into a homogeneous medium. The expressions are given for the vector potential and for the electric and magnetic fields. The spectral distributions are studied for three types of radiation: (i) Cherenkov radiation (CR) in the exterior medium, (ii) radiation on the guided modes of the dielectric cylinder, and (iii) emission of surface polaritons. Unlike the first two types of radiation, there is no velocity threshold for the generation of surface polaritons. The corresponding radiation is present in the spectral range where the dielectric permittivities of the cylinder and surrounding medium have opposite signs. The spectral range of the emitted surface polaritons becomes narrower with decreasing energy of the particle. The general results are illustrated for a special case of the Drude model for dispersion of the dielectric permittivity of the cylinder. We show that the presence of the cylinder may lead to the appearance of strong narrow peaks in the spectral distribution of the CR in the exterior medium. The conditions are specified for the appearance of those peaks and the corresponding heights and widths are analytically estimated. The collective effects of particles in bunches are discussed.

9 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the intensity distribution structure obtained at second- and fourth-harmonic generation can be retained by introducing an angular chirp.
Abstract: A method for shaping periodic intensity distributions of strongly chirped picosecond laser pulses in the infrared range by periodic phase modulation of the spectrum is proposed. The dependence of the time modulation period and depth on the parameters of periodic phase modulation of the spectrum is analyzed by analytical and numerical methods. It is demonstrated that the intensity distribution structure obtained at second- and fourth-harmonic generation can be retained by introducing an angular chirp. The electron bunch dynamics at the photoinjector test facility at DESY in Zeuthen (PITZ) was modeled numerically using ellipsoidal laser pulses with intensity modulation.

8 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a compact and powerful narrowband terahertz (1-20 THz) source based on laser wakefield acceleration and high gradient dielectric lined structures.
Abstract: The advancement of the techniques of producing electromagnetic radiation in the terahertz range (1--20 THz) attracts a wide range of potential applications and the quest for powerful THz sources is ever-increasing. The means to generate THz is an active research field and the energy per pulse is limited due to breakdown of the medium used. In this paper, we propose a compact yet powerful narrowband THz source based on two pillars of active research in the field of novel accelerators: laser plasma wakefield acceleration and high gradient dielectric lined structures. The laser plasma wakefield (LPW) injector is used to provide the relativistic electron bunches to an interaction tube, a dielectric lined waveguide (DLW), in order to generate THz. Due to the high gradient nature of both devices, the combination ends up with a very compact solution for mJ scale THz pulse generation. Potentially these pulses can be used as drivers for nonlinear phenomena in condensed matter, which can be probed using ultrashort x-ray pulses at the same free electron laser facility.

7 citations

Journal ArticleDOI
TL;DR: An optically pumped gas terahertz fiber laser based on gold-coated quartz hollow-core fiber with output power of 110 mW is demonstrated, confirming the possibility of a compact flexible optically pumps gas terAhertz Fiber laser.
Abstract: An optically pumped gas terahertz fiber laser based on gold-coated quartz hollow-core fiber is demonstrated. When the terahertz fiber laser is filled with methanol gas and pumped by a piezoelectric-ceramic-transducer-adjusted transversely excited atmospheric pressure carbon dioxide laser, a continuous 2.52 THz laser with the output power of 110 mW is obtained. Attributed to the adjustment of the piezoelectric ceramic transducer in the carbon dioxide laser, the fluctuation of the terahertz fiber laser output power is controlled within ±5%. The result confirms the possibility of a compact flexible optically pumped gas terahertz fiber laser.

5 citations

Journal ArticleDOI
TL;DR: In this article, experimental investigations of the THz radiation generated from a corrugated and a non-corrugated capillary with reflectors, using a femtosecond electron beam of LUCX accelerator at KEK, Japan.
Abstract: In this report we present experimental investigations of the THz radiation generated from a corrugated and a non-corrugated capillary with reflectors, using a femtosecond electron beam of LUCX accelerator at KEK, Japan. We discuss measurements of the radiation angular distributions and their comparison with Particle In Cell simulations, and also investigate an off-central propagation of the beam in the capillaries based on experimental measurements and simulations.

5 citations