Self-Amplified Spontaneous Emission Free-Electron Laser with an Energy-Chirped Electron Beam and Undulator Tapering

Giannessi, L.; Bacci, A.; Bellaveglia, M.; Briquez, F.; Castellano, M.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Couprie, M.E.; Cultrera, L.; Dattoli, G.; Filippetto, D.; Franco, M.; Pirro, G. Di; Ferrario, M.; Ficcadenti, L.; Frassetto, Fabio; Gallo, A.; Gatti, G.; Labat, M.; Marcus, Gabriel; Moreno, Marco P.; Mostacci, A.; Pace, E.; Petralia, A.; Petrillo, V.; Poletto, Luca; Quattromini, M.; Rau, Julietta V.; Ronsivalle, C.; Rosenzweig, J.; Rossi, A. R.; Albertini, V. Rossi; Sabia, E.; Serluca, M.; Spampinati, S.; Spassovsky, I.; Spataro, B.; Surrenti, V.; Vaccarezza, C.; Vicario, C.

doi:10.1103/physrevlett.106.144801

Cited by 69 publications

(42 citation statements)

References 31 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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“…Several techniques have been explored to increase longitudinal coherence, stability, and/or to shorten the FEL pulse time scale towards the attosecond domain. The amplification of one single SASE spike has been demonstrated by compressing the electron beam close or below the FEL coherence length [15,16], by using a chirped bunch energy combined with a matched undulator taper [17][18][19], or by spoiling the whole electron beam except a limited fraction [20,21], a technique that has also been implemented to produce double pulse two-color radiation for pump and probe experiments [22]. Short single or multiple pulses have also been produced in seeded or cascaded FELs [23][24][25][26][27], with increased coherence and shot to shot stability.…”

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Observation of Time-Domain Modulation of Free-Electron-Laser Pulses by Multipeaked Electron-Energy Spectrum

et al. 2013

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We present the experimental demonstration of a new scheme for the generation of ultrashort pulse trains based on free-electron-laser (FEL) emission from a multipeaked electron energy distribution. Two electron beamlets with energy difference larger than the FEL parameter have been generated by illuminating the cathode with two ps-spaced laser pulses, followed by a rotation of the longitudinal phase space by velocity bunching in the linac. The resulting self-amplified spontaneous emission FEL radiation, measured through frequency-resolved optical gating diagnostics, reveals a double-peaked spectrum and a temporally modulated pulse structure. DOI: 10.1103/PhysRevLett.111.114802 PACS numbers: 41.60.Cr, 42.55.Àf, 42.65.Ky Radiation pulses with attosecond to femtosecond time scales represent a real possibility for a breakthrough in science and technology, permitting unprecedented insights into the ultrafast electron and nuclear dynamics [1][2][3]. The time-resolved study of electron rearrangements could lead to significant advances in the understanding of intermolecular processes, chemical bond breaking and formation, and the interaction of photoactivated molecules with their environment.Trains of ultrashort radiation pulses enable stroboscopic electron imaging [4] and the investigation of the response accompanying collective electron motion in nanomaterials [5]. They also find further applications in other technical fields, such as the enhancement of transmission or reflectivity in materials, resonant inelastic x-ray scattering, or the ab initio phasing of nanocrystals [6].Sequences of spikes have been synthesized by means of the high harmonic generation driven by lasers in gases [7] and regularly used in experiments [4,8], but are severely limited in efficiency approaching the keV range.Free-electron lasers (FELs) are capable of producing high brightness pulses in the x-ray spectral region [9][10][11][12]. The FEL, in the self-amplified spontaneous emission (SASE) mode of operation [13], generates radiation with limited temporal coherence [14], time duration of the order of the electron bunch length and structured in a chaotic succession of random peaks. The typical time scale of these radiation spikes is set by the FEL Pierce parameter [13]. Several techniques have been explored to increase longitudinal coherence, stability, and/or to shorten the FEL pulse time scale towards the attosecond domain. The amplification of one single SASE spike has been demonstrated by compressing the electron beam close or below the FEL coherence length [15,16], by using a chirped bunch energy combined with a matched undulator taper [17][18][19], or by spoiling the whole electron beam except a limited fraction [20,21], a technique that has also been implemented to produce double pulse two-color radiation for pump and probe experiments [22]. Short single or multiple pulses have also been produced in seeded or cascaded FELs [23][24][25][26][27], with increased coherence and shot to shot stability. More sophisticated seeding concept...

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“…The double peak structure in the electron distribution was generated by illuminating the photocathode with a comb laser consisting of two pulses hundreds fs long separated by 4 ps [17]. The emitted ps-spaced electron beam was then injected in the first of the three S band sections of the linac close to the zero-crossing radio frequency (rf) field phase, where it is compressed by velocity bunching [18][19][20]. The e beam was then extracted at the maximum compression, where the two beamlets are overlapped in time and separated in energy.…”

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Two-Color Radiation Generated in a Seeded Free-Electron Laser with Two Electron Beams

et al. 2015

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We present the experimental evidence of the generation of coherent and statistically stable two-color free-electron laser radiation obtained by seeding an electron beam double peaked in energy with a laser pulse single spiked in frequency. The radiation presents two neat spectral lines, with time delay, frequency separation, and relative intensity that can be accurately controlled. The analysis of the emitted radiation shows a temporal coherence and a shot-to-shot regularity in frequency significantly enhanced with respect to the self-amplified spontaneous emission. DOI: 10.1103/PhysRevLett.115.014801 PACS numbers: 41.60.Cr, 41.50.+h, 42.55.Vc Two-color radiation enables a wide number of new experiments, ranging from time-resolved analysis of the atomic, surface, and plasma dynamics to the imaging of biomedical samples and molecules. Studies on dual frequency production on free-electron lasers (FELs) have been recently carried on with different methods [1][2][3][4][5] in various frequency regimes, while, at the same time, several promising theoretical proposals have been investigated, aimed at generating two-color FEL emission in the x-ray wavelength range [6][7][8][9]. A particularly powerful method for producing two-color radiation is the double electron bunch operation that has been implemented and demonstrated in the visible [2,10,11] and in the x-ray [5] domains, in this latter case with applications on experiments with external users. This scheme is based on two closely spaced electron beamlets generated at the cathode and accelerated off crest along the linac to two different energies. The bunch train, driven in the undulator, radiates two distinct self-amplified spontaneous emission (SASE) pulses, whose relative time delay and wavelength difference can be tuned independently by changing the extraction conditions from the linac. The particular advantage of this approach is the large spectral separation, up to 1-2% [10], that can be achieved and the possibility of using the entire undulator length on both colors, thus allowing applications requiring high-intensity radiation or exploiting the activation of self-seeding processes. In all these previous experiments, the emission starts from noise and, whereas the two colors can be single spiked, the radiation is affected by random shot-to-shot fluctuations both in the time and frequency domains and presents, therefore, poor longitudinal coherence. The degree of coherence can be improved by seeding the radiation with a temporally coherent external field. This technique covers directly all the radiation frequencies where coherent sources are available. In particular, atomic lasers can be used to seed radiation in their range of operation. The use of the laser harmonics extends this method to ultraviolet [12], while the combination of high-gain harmonics generation (HGHG) with multistage cascade schemes permits to reach, at the status of the art, the water window [13].In this Letter, we present an experimental demonstration of the operation with a seed, sing...

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Self-Amplified Spontaneous Emission Free-Electron Laser with an Energy-Chirped Electron Beam and Undulator Tapering

Cited by 69 publications

References 31 publications

Characterization of the THz radiation source at the Frascati linear accelerator

Characterization of the THz radiation source at the Frascati linear accelerator

Observation of Time-Domain Modulation of Free-Electron-Laser Pulses by Multipeaked Electron-Energy Spectrum

Two-Color Radiation Generated in a Seeded Free-Electron Laser with Two Electron Beams

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