Nonlinear Harmonic Generation in Free-Electron Lasers with Helical Wigglers

Freund, H.P.; O'Shea, P.G.; Biedron, Sandra

doi:10.1103/physrevlett.94.074802

Cited by 11 publications

(27 citation statements)

References 18 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a FEL, harmonic generation is driven by the electron-beam interaction with a radiation at a given fundamental wavelength, in the presence of the static and periodic magnetic field generated by an undulator [7][8][9][10][11][12][13][14]. Such interaction produces a significant modulation (called bunching) of the electron-beam density at the fundamental wavelength, and its harmonics.…”

Section: Introductionmentioning

confidence: 99%

Angular distribution of nonlinear harmonic generation in helical undulators: A comparison between experiments and theory

Allaria¹,

Ninno²,

Geloni³

et al. 2011

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

Using harmonic emission from circularly polarized undulator is a procedure that is normally employed on synchrotron beamlines in order to extend the covered spectral range. A similar capability is likewise beneficial for next generation free-electron lasers. In this paper, we perform a first quantitative experimental analysis of the angular distribution of free-electron laser harmonic emission from helical undulators. Experimental results are compared to those obtained by means of a theoretical model based on the paraxial solution of Maxwell's equations.PACS numbers:

show abstract

Section: Introductionmentioning

confidence: 99%

Angular distribution of nonlinear harmonic generation in helical undulators: A comparison between experiments and theory

Allaria¹,

Ninno²,

Geloni³

et al. 2011

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

show abstract

“…In this context, an open point that is stimulating an animated dispute in the FEL community [11] concerns the possibility for helical undulators to generate significant coherent on-axis signal. In particular, recent theoretical results [9] suggest that the NHG signal, whose characterization is also discussed in [6], should be concentrated off-axis.…”

mentioning

confidence: 98%

“…During recent years significant effort has been devoted to the theoretical investigation of the process of coherent harmonic generation in free electron lasers (FELs) [1][2][3][4][5][6][7][8][9]. Such effort is motivated by interest in developing new light sources in the vacuum ultraviolet (VUV) and x-ray spectral regions.…”

mentioning

confidence: 99%

“…Following established nomenclature, we will refer to this process as nonlinear harmonic generation (NGH). The fact that coherent signal is produced at a harmonic of the resonant wavelength determines some of the radiation characteristics [1,6,7]. In particular, it has been demonstrated [1,10] that, in the case of planar undulators, on-axis emission occurs exclusively at odd harmonics, while even harmonics are present only off-axis, and with some peculiar polarization properties [1,7,8].…”

mentioning

confidence: 99%

“…According to theoretical predictions [1], the signal should be zero in the case of linearly polarized undulators. As already mentioned, the existence of a nonzero signal in the case of helical undulators is still an open question [6,9,16], which is lively debated in the FEL community [11].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Experimental Characterization of Nonlinear Harmonic Generation in Planar and Helical Undulators

et al. 2008

View full text Add to dashboard Cite

We present an experimental characterization of the process of coherent harmonic generation in single-pass free electron lasers. The harmonic radiation is obtained by seeding the electron beam stored in the Elettra storage ring with a Ti:sapphire laser. Different methods for generating harmonics are compared between them, and a detailed characterization of the emitted light is performed for different polarizations. Our results also contribute to the debate about the possible presence of a coherent on-axis signal in helical undulators. In this respect, we provide an experimental confirmation of recent theoretical studies that predict no coherent on-axis signal.

show abstract

X radiation sources based on accelerators

Couprie

Filhol

2008

Comptes Rendus. Physique

View full text Add to dashboard Cite

Light sources based on accelerators aim at producing very high brilliance coherent radiation, tuneable from the infrared to X-ray range, with picosecond or femtosecond light pulses.The first synchrotron light sources were built around storage rings in which a large number of relativistic electrons produce "synchrotron radiation" when their trajectory is subjected to a magnetic field, either in bending magnets or in specific insertion devices (undulators), made of an alternating series of magnets, allowing the number of curvatures to be increased and the radiation to be reinforced.These "synchrotron radiation" storage rings are now used worldwide (there are more than thirty), and they simultaneously distribute their radiation to several tens of users around the storage ring.The most effective installations in term of brilliance are the so-called 3rd generation synchrotron radiation light sources. The radiation produced presents pulse durations of the order of a few tens of ps, at a high rate (of the order of MHz); it is tuneable over a large range, depending on the magnetic field and the electron beam energy and its polarisation is adjustable (in the VUV-soft-X range). Generally, a very precise spectral selection is made by the users with a monochromator.The single pass linear accelerators can produce very short electron bunches (∼ 100 femtosecond). The beam of very high electronic density is sent into successive undulator modules, reinforcing the radiation's longitudinal coherence, produced according to a Free Electron Laser (FEL) scheme by the interaction between the electron bunch and a light wave. The very high peak brilliance justifies their designation as 4th generation sources. The number of users is smaller because an electron pulse produces a radiation burst towards only one beamline. Energy Recovery Linacs (ERL) let the beam pass several times in the accelerator structures either to recover the energy or to accelerate the electrons during several turns, and thus provide subpicosecond beams for a greater number of users.A state-of-the-art of X sources using conventional (and not laser plasma based) accelerators is given here, underlying the performance already reached or forecast and the essential challenges.

show abstract

Nonlinear Harmonic Generation in Free-Electron Lasers with Helical Wigglers

Cited by 11 publications

References 18 publications

Angular distribution of nonlinear harmonic generation in helical undulators: A comparison between experiments and theory

Angular distribution of nonlinear harmonic generation in helical undulators: A comparison between experiments and theory

Experimental Characterization of Nonlinear Harmonic Generation in Planar and Helical Undulators

X radiation sources based on accelerators

Contact Info

Product

Resources

About