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1.
Using the recently proposed echo-enabled harmonic generation (EEHG) free-electron laser (FEL) scheme, it is shown that operating the Shanghai deep ultraviolet FEL (SDUV-FEL) with single-stage to higher harmonics is very promising, with higher frequency up-conversion effciency, higher harmonic selectivity and lower power requirement of the seed laser. The considerations on a proof-of-principle experiment and expected performance in SDUV-FEL are given. 相似文献
2.
With the right choice of parameters in the free electron laser (FEL) scheme, the undulator can be primarily operated at high order harmonic modes and the harmonic radiation is expected to be significantly enhanced. Recently, the possibility of proof-of-principle harmonic operation experiments on the basis of the Shanghai deep ultraviolet (SDUV) FEL test facility has been studied. In this paper, the principle of harmonic operation, three dimensional numerical approaches, and detailed performances of proposed harmonic operation at SDUV FEL are presented. 相似文献
3.
null 《中国物理C(英文版)》2016,40(9):098102-098102
We study a self-seeded high-gain harmonic generation(HGHG) free-electron laser(FEL) scheme to extend the wavelength of a soft X-ray FEL. This scheme uses a regular self-seeding monochromator to generate a seed laser at the wavelength of 1.52 nm, followed by a HGHG configuration to produce coherent, narrow-bandwidth harmonic radiations at the GW level. The 2nd and 3rd harmonic radiation is investigated with start-to-end simulations.Detailed studies of the FEL performance and shot-to-shot fluctuations are presented. 相似文献
4.
Tremaine A Wang XJ Babzien M Ben-Zvi I Cornacchia M Nuhn HD Malone R Murokh A Pellegrini C Reiche S Rosenzweig J Yakimenko V 《Physical review letters》2002,88(20):204801
Nonlinear harmonic radiation was observed using the VISA self-amplified, spontaneous emission (SASE) free-electron laser (FEL) at saturation. The gain lengths, spectra, and energies of the three lowest SASE FEL modes were experimentally characterized. The measured nonlinear harmonic gain lengths and center spectral wavelengths decrease with harmonic number, n, which is consistent with nonlinear harmonic theory. Both the second and third nonlinear harmonics energies are about 1% of the fundamental energy. These experimental results demonstrate for the first time the feasibility of using nonlinear harmonic SASE FEL radiation to produce coherent, femtosecond x rays. 相似文献
5.
K. V. Zhukovsky 《Moscow University Physics Bulletin》2018,73(4):364-371
Generation of X-ray radiation in a cascade self-amplified spontaneous emission free-electron laser (SASE FEL) using the harmonics of a two-frequency undulator is studied. The advanced phenomenological model of a one-pass FEL that accounts for the main losses in real FELs is presented: the electron energy spread in the beam, the beam divergence, diffraction, and the fact that emission losses are greater at higher harmonics than in the main frequency range. The FEL mathematical model was performed using the Mathematica software and calibrated within the experiment carried out at the operating SPARC facility via complex three-dimensional numerical simulations. The phenomenological model is used to analyze FEL dynamics for generation of a high-energy X-ray emission at a relatively short length. It is proposed to use a two-frequency undulator for the initial electron grouping and subsequent frequency multiplication in a cascade FEL with higher harmonic amplification (HGHG). The advantages of the two-frequency undulator are presented for electron grouping at higher harmonics of the undulator radiation (UR). The operation of several types of FEL is simulated with amplification of the seed laser wave frequency in two and three cascades to generate the soft X-ray radiation. A seed laser with a wavelength of 11.43 nm corresponding to the peak reflectivity of mirror coatings with MoRu/Be is proposed for generating the intensive X-ray laser radiation with λ ~ 1.27–3.37 nm. Here, the intensive radiation power reaches 50 MW at a length of only 35 meters; the radiation shows good temporal coherence corresponding to the performance of a low-power seed laser with a lower frequency. 相似文献
6.
With the right choice of parameters in the free electron laser (FEL) scheme, the undulator can be primarily operated at high order harmonic modes and the harmonic radiation is expected to be significantly enhanced. Recently, the possibility of proof-of-principle harmonic operation experiments on the basis of the Shanghai deep ultraviolet (SDUV) FEL test facility has been studied. In this paper, the principle of harmonic operation, three dimensional numerical approaches, and detailed performances of proposed harmonic operation at SDUV FEL are presented. 相似文献
7.
We report for the first time to our knowledge the experimental realization of a storage ring free-electron laser (FEL) in the middle-infrared (MIR) region. A technique to adjust the optical cavity using higher harmonic FELs was developed for a fundamental FEL in the MIR region. The MIR FELs were oscillated in the wavelength region of 2475 to 2673 nm, and the relative linewidth was 5×10??. A quasi-monochromatic x-ray beam with an energy of 700 keV was generated using FEL Compton backscattering. We were able to realize a quasi-monochromatic x-ray beam, whose energy is difficult to generate even in advanced synchrotron radiation facilities. 相似文献
8.
In high gain harmonic generation (HGHG) free electron laser (FEL), with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation (HO) mode. In this paper, we investigate HO of HGHG FEL. Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy. 相似文献
9.
In high gain harmonic generation (HGHG) free electron laser (FEL), with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation (HO) mode. In this paper, we investigate HO of HGHG FEL.Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy. 相似文献
10.
Laser-beam interaction in an undulator is commonly suggested in the development of free electron laser(FEL)schemes. In this paper, a three-dimensional algorithm is developed to assist in laser-beam interaction simulation in an undulator, which is built on the basis of the fundamentals of electrodynamics, i.e.the electron's behavior is determined by the magnetic field and the laser electric field in the time domain. On the basis of the algorithm, the detuning effect in a laser heater, the carrier envelope phase effect of a few-cycle laser in attosecond X-ray FEL schemes and output wavelength tuning in a high gain harmonic generation FEL are numerically discussed. 相似文献
11.
Labat M Bellaveglia M Bougeard M Carré B Ciocci F Chiadroni E Cianchi A Couprie ME Cultrera L Del Franco M Di Pirro G Drago A Ferrario M Filippetto D Frassetto F Gallo A Garzella D Gatti G Giannessi L Lambert G Mostacci A Petralia A Petrillo V Poletto L Quattromini M Rau JV Ronsivalle C Sabia E Serluca M Spassovsky I Surrenti V Vaccarezza C Vicario C 《Physical review letters》2011,107(22):224801
The injection of a seed in a free-electron laser (FEL) amplifier reduces the saturation length and improves the longitudinal coherence. A cascaded FEL, operating in the high-gain harmonic-generation regime, allows us to extend the beneficial effects of the seed to shorter wavelengths. We report on the first operation of a high-gain harmonic-generation free-electron laser, seeded with harmonics generated in gas. The third harmonics of a Ti:sapphire laser, generated in a gas cell, has been amplified and up-converted to its second harmonic (λ(rad)=133 nm) in a FEL cascaded configuration based on a variable number of modulators and radiators. We studied the transition between coherent harmonic generation and superradiant regime, optimizing the laser performances with respect to the number of modulators and radiators. 相似文献
12.
In a Storage Ring Free Electron Laser (SRFEL) there is a
strong interdependence between the laser beam and the electron
beam from which the laser is generated. The Super ACO storage ring
has a second Radio Frequency (RF) cavity at the 5th harmonic of
the main RF cavity. It is used to shorten the bunch length,
thereby enhancing the laser gain. Employing this RF harmonic
cavity instabilities are observed with a strong effect on both the
laser radiation properties and the electron beam behaviour. In
this paper, we first present beam characteristics of Super-ACO as
influenced by the harmonic cavity, and the instabilities of the
beam due to this RF cavity. Then we discuss the FEL properties in
presence of the harmonic RF cavity. In general the harmonic cavity
functions as intended, and it is observed that the laser
suppresses the instabilities caused by the harmonic cavity in the
absence of the FEL. 相似文献
13.
The performance of a free electron laser (FEL) using a low-power extreme ultraviolet (EUV) pulse as an input seed is investigated. The parameters are appropriate for 30 nm seeds produced from high-power Ti:Sapphire pulses using high harmonic generation schemes. It is found that, for reasonable beam parameters, robust FEL performance can be obtained. Both time-independent and time-dependent simulations are performed for varying system parameters using the GENESIS simulation code. A comparison is made with a two-stage harmonic FEL that is seeded by a high-power Ti:Sapphire pulse. 相似文献
14.
Yu LH DiMauro L Doyuran A Graves WS Johnson ED Heese R Krinsky S Loos H Murphy JB Rakowsky G Rose J Shaftan T Sheehy B Skaritka J Wang XJ Wu Z 《Physical review letters》2003,91(7):074801
We report the first experimental results on a high-gain harmonic-generation (HGHG) free-electron laser (FEL) operating in the ultraviolet. An 800 nm seed from a Ti:sapphire laser has been used to produce saturated amplified radiation at the 266 nm third harmonic. The results confirm the predictions for HGHG FEL operation: stable central wavelength, narrow bandwidth, and small pulse-energy fluctuation. 相似文献
15.
16.
Cascading stages of high gain harmonic generation free electron laser (FEL) seem to be a feasible way to generate short wavelength radiation. With help of the analytical estimates, we design a two-stage cascading scheme to achieve 131 nm DUV radiation on the basis of the Shanghai deep ultraviolet free electron laser test facility. Detailed studies on the FEL performance, the stability and the sensitivity of the output power to parameter variation have been achieved by GENESIS1.3, and design of the lattice structure is presented. 相似文献
17.
Technical Physics - Evolution of bunching and harmonic power is theoretically studied for a single-pass free-electron laser (FEL) in which electrons are periodically phase-shifted relative to... 相似文献
18.
DENG Hai-Xiao 《中国物理C(英文版)》2010,34(10)
The echo-enabled harmonic generation(EEHG)scheme offers remarkable efficiency for generatinghigh harmonic microbunching with a relatively small energy modulation.A proof of principle experiment of the EEHG scheme has been proposed at the Shanghai deep ultraviolet(SDUV)free electron laser(FEL)facility,where the 4th harmonic of the seed laser is amplified in the 9 m long radiator.To explore the advantages of the EEHG scheme,in this paper,a method of measuring the coherent high harmonic radiation of the radiator is proposed to investigate the electron beam microbunching corresponding to the 10th-20th harmonics of the seed laser.The principle of the proposed method,comparisons with existing methods and the simulation results are presented and discussed. 相似文献
19.
通过三维磁场的有限元计算,给出了自由电子激光(FEL)研究用光学速调管升级后的磁参数。国家同步辐射实验室合肥光源(HLS)电子储存环能量可以日常运行在200~800 MeV间,为了与电子储存环能量匹配,并在较高束电子能量下进行实验和得到较多的相干辐射光子,光学速调管从原来的对称结构升级成非对称结构,用于HLS储存环谐波产生FEL实验。给出了升级后非对称光学速调管的几组匹配磁参数,用于在HLS储存环注入能量和可以运行的最高能量下进行谐波FEL实验。初步计算表明,HLS 储存环电子束性能优越,能散很低,FEL实验用最高能散仅为2.05×10-4,相应FEL辐射的能散修正因子在0.96以上,可以忽略不计。 相似文献
20.
基于自由电子激光器的能量模型,在具有螺旋磁场自由电子激光器中,本文采用一种简单的方法处理了强信号条件下能量转换过程.讨论了饱和产生的过程和初始能量色散对饱和影响的机制.这种处理方法也适用于自由电子激光器的谐波辐射. 相似文献