High-Gain Harmonic-Generation Free-Electron Laser Seeded by Harmonics Generated in Gas

Labat, M.; Bellaveglia, M.; Bougeard, M.; Carré, B.; Ciocci, F.; Chiadroni, E.; Cianchi, A.; Couprie, M.E.; Cultrera, L.; Franco, M.; Pirro, G. Di; Drago, A.; Ferrario, M.; Filippetto, D.; Frassetto, Fabio; Gallo, A.; Garzella, D.; Gatti, G.; Giannessi, L.; Lambert, Guillaume; Mostacci, A.; Petralia, A.; Petrillo, V.; Poletto, Luca; Quattromini, M.; Rau, Julietta V.; Ronsivalle, C.; Sabia, E.; Serluca, M.; Spassovsky, I.; Surrenti, V.; Vaccarezza, C.; Vicario, C.

doi:10.1103/physrevlett.107.224801

Cited by 81 publications

(45 citation statements)

References 29 publications

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“…THz, [31][32][33] Compton, etc., to novel schemes for generation of FEL radiation, [34][35][36][37] to plasma acceleration experiments. 38,39 In the following, we will focus on the activity concerning the generation, characterization and transport of both a high brightness single pulse electron beam and a multi-pulses train through the dogleg beamline down to the THz station, for the development of high peak power, both broadband and narrowband THz radiation, whose experimental layout is described in Sec.…”

Section: The Sparc-lab Test Facilitymentioning

confidence: 99%

Characterization of the THz radiation source at the Frascati linear accelerator

Chiadroni

Bellaveglia

Calvani

et al. 2013

Review of Scientific Instruments

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Material selection considerations for coaxial, ferrimagnetic-based nonlinear transmission lines J. Appl. Phys. 113, 064904 (2013) Graphene on boron nitride microwave transistors driven by graphene nanoribbon back-gates Appl. Phys. Lett. 102, 033505 (2013) Millimeter scale electrostatic mirror with sub-wavelength holes for terahertz wave scanning Appl. Phys. Lett. 102, 031111 (2013) Leaky and bound modes in terahertz metasurfaces made of transmission-line metamaterials J. Appl. Phys. 113, 033105 (2013) Additional information on Rev. Sci. Instrum. The linac driven coherent THz radiation source at the SPARC-LAB test facility is able to deliver broadband THz pulses with femtosecond shaping. In addition, high peak power, narrow spectral bandwidth THz radiation can be also generated, taking advantage of advanced electron beam manipulation techniques, able to generate an adjustable train of electron bunches with a sub-picosecond length and with sub-picosecond spacing. The paper reports on the manipulation, characterization, and transport of the electron beam in the bending line transporting the beam down to the THz station, where different coherent transition radiation spectra have been measured and studied with the aim to optimize the THz radiation performances.

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Section: The Sparc-lab Test Facilitymentioning

confidence: 99%

Characterization of the THz radiation source at the Frascati linear accelerator

Chiadroni

Bellaveglia

Calvani

et al. 2013

Review of Scientific Instruments

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“…The FEL pulse duration is typically specified by users in facilities relying on SASE, whilst its lower-limit is set by the duration of the external seed laser, such as in High Gain Harmonic Generation (HGHG) schemes [10,15,16,[33][34][35][36][37]. In both cases, the electron bunch duration at the undulator should be longer than the required FEL pulse duration because of effects such as FEL slippage in SASE FELs, arrival time jitter, and multi-stage cascade in HGHG FELs.…”

Section: Pulse Length-driven Approachmentioning

confidence: 99%

On the Importance of Electron Beam Brightness in High Gain Free Electron Lasers

Mitri

2015

Photonics

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Linear accelerators delivering high brightness electron beams are essential for driving short wavelength, high gain free-electron lasers (FELs). The FEL radiation output efficiency is often parametrized through the power gain length that relates FEL performance to electron beam quality at the undulator. In this review article we illustrate some approaches to the preliminary design of FEL linac-drivers, and analyze the relationship between the output FEL wavelength, exponential gain length and electron beam brightness. We extend the discussion to include FEL three-dimensional effects and electron beam projected emittances. Although mostly concentrating on FELs based upon self-amplified spontaneous emission (SASE), our findings are in some cases highly relevant to externally seeded FELs.

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“…In superradiance, the radiation pulse length sr is a function of the FEL peak power, decreases as sr / z À1=2 (z is the distance along the undulator), and can become significantly shorter than that of the input seed laser [16]. The peak power P sr increases as P sr / z 2 and the pulse energy E sr scales as E sr % P sr sr / z 3=2 [16][17][18][19][20].Seeded FELs can operate either in the amplifier ''direct seeding'' scheme, or in the high gain harmonic generation (HGHG) configuration [21][22][23][24], where the seed in a first undulator (modulator) is used to induce an energy-density modulation in the electron beam longitudinal phase space. This bunched beam then emits a higher order harmonics rad ¼ seed =n in a following undulator (radiator).…”

mentioning

confidence: 99%

“…Seeded FELs can operate either in the amplifier ''direct seeding'' scheme, or in the high gain harmonic generation (HGHG) configuration [21][22][23][24], where the seed in a first undulator (modulator) is used to induce an energy-density modulation in the electron beam longitudinal phase space. This bunched beam then emits a higher order harmonics rad ¼ seed =n in a following undulator (radiator).…”

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Superradiant Cascade in a Seeded Free-Electron Laser

Giannessi¹,

Bellaveglia

Chiadroni

et al. 2013

Phys. Rev. Lett.

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We report measurements demonstrating the concept of the free-electron laser (FEL) superradiant cascade. Radiation ( rad ¼ 200 nm) at the second harmonic of a short, intense seed laser pulse ( seed ¼ 400 nm) was generated by the cascaded FEL scheme at the transition between the modulator and radiator undulator sections. The superradiance of the ultrashort pulse is confirmed by detailed measurements of the resulting spectral structure, the intensity level of the produced harmonics, and the trend of the energy growth along the undulator. These results are compared to numerical particle simulations using the FEL code GENESIS 1.3 and show a satisfactory agreement. Fourth generation light sources open the way towards the exploration of molecular and atomic phenomena, yielding unprecedented benefits to a wide range of scientific disciplines [1][2][3][4][5][6]. Free-electron lasers (FELs), operating in self-amplified spontaneous emission (SASE) mode, have demonstrated the capability of reaching the subnanometer wavelength range at the femtosecond time scale [7,8]. The multielectron dynamics in atoms and molecules involved in chemical transformation processes evolves on a femtoto attosecond time domain. Thus, ultrashort pulses in the XUV spectral range are the potential tool to control and map the collective electronic and nuclei rearrangements. In a SASE FEL the generation of radiation is due to the passage of a relativistic electron beam through the periodic magnetic field of an undulator with maximum field amplitude B u and period u , inducing emission at a resonant2 (linear undulator) and its higher order harmonics, where is the Lorentz factor of the electrons and K ¼ eB u u =ð2m e cÞ the deflection parameter of the undulator. At the onset of saturation, the electrons emit coherently [9] over a characteristic frequency bandwidth Á!=! $ , where is the Pierce parameter [10,11]. Considering that typical values of the Pierce parameter range from 10 À3 to 10 À4 , the associated FWHM pulse length at the Fourier limit is ¼ 2 ffiffiffiffiffiffiffiffiffiffiffiffiffi ffi 2 lnð2Þ p L c =c, where L c ¼ rad =4 is known as cooperation length and, at rad ¼ 1 nm, assumes values in the range c $ 0:6-6 fs. When the electron bunch is longer than L c , several independent processes of SASE amplification can occur, leading to a pulse structure far from the Fourier limit and composed of a number of independent spikes [12]. A selective amplification of only one of these spikes has been demonstrated by shaping the electron beam phase space, in order to enable the field growth only in a limited portion of the bunch [13,14]. A single mode may also be generated by seeding the FEL amplifier with an external source. Seeding with a pulse shorter than c results in a spike of rms duration given by the cooperation length, at the onset of saturation when P sat % P beam (P beam is the electron beam power). Pulses shorter than the cooperation length may still be obtained at intensities higher than the saturation level, when the FEL emits in the superra...

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High-Gain Harmonic-Generation Free-Electron Laser Seeded by Harmonics Generated in Gas

Cited by 81 publications

References 29 publications

Characterization of the THz radiation source at the Frascati linear accelerator

Characterization of the THz radiation source at the Frascati linear accelerator

On the Importance of Electron Beam Brightness in High Gain Free Electron Lasers

Superradiant Cascade in a Seeded Free-Electron Laser

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