Third Harmonic Lasing in a Storage Ring Free-Electron Laser

Sei, N.; Ogawa, Hiroshi; Yamada, Ken‐ichi

doi:10.1143/jpsj.79.093501

Cited by 19 publications

(22 citation statements)

References 18 publications

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“…An alternative option is a harmonic lasing that was first proposed for FEL oscillators [12], and was experimentally demonstrated in infrared and optical wavelength ranges for oscillator configurations [13][14][15][16]. Harmonic lasing in single-pass high-gain FELs [5,7,17,18], i.e., the radiative instability at an odd harmonic of the planar undulator developing independently from lasing at the fundamental wavelength, might have significant advantages over nonlinear harmonic generation (much higher power, much better stability, smaller bandwidth, and no necessity in filters), provided that lasing at the fundamental frequency is suppressed (for lasing at the 3rd harmonic) [19].…”

Section: Introductionmentioning

confidence: 99%

Harmonic lasing in x-ray free electron lasers

Schneidmiller

Yurkov

2012

Phys. Rev. ST Accel. Beams

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Harmonic lasing in a free electron laser with a planar undulator (under the condition that the fundamental frequency is suppressed) might be a cheap and efficient way of extension of wavelength ranges of existing and planned x-ray free electron laser (FEL) facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam which is easier to handle due to the suppressed fundamental frequency. In this paper we perform a parametrization of the solution of the eigenvalue equation for lasing at odd harmonics, and present an explicit expression for FEL gain length, taking into account all essential effects. We propose and discuss methods for suppression of the fundamental harmonic. We also suggest a combined use of harmonic lasing and lasing at the retuned fundamental wavelength in order to reduce bandwidth and to increase brilliance of x-ray beam at saturation. Considering 3rd harmonic lasing as a practical example, we come to the conclusion that it is much more robust than usually thought, and can be widely used in the existing or planned x-ray FEL (XFEL) facilities. In particular, Linac Coherent Light Source (LCLS) after a minor modification can lase to saturation at the 3rd harmonic up to the photon energy of 25-30 keV providing multigigawatt power level and narrow bandwidth. As for the European XFEL, harmonic lasing would allow one to extend operating range (ultimately up to 100 keV), to reduce FEL bandwidth and to increase brilliance, to enable two-color operation for pump-probe experiments, and to provide more flexible operation at different electron energies. Similar improvements can be realized in other x-ray FEL facilities with gap-tunable undulators like FLASH II, SACLA, LCLS II, etc. Harmonic lasing can be an attractive option for compact x-ray FELs (driven by electron beams with a relatively low energy), allowing the use of the standard undulator technology instead of small-gap in-vacuum devices. Finally, in this paper we discover that in a part of the parameter space, corresponding to the operating range of soft x-ray beam lines of x-ray FEL facilities (like SASE3 beam line of the European XFEL), harmonics can grow faster than the fundamental wavelength. This feature can be used in some experiments, but might also be an unwanted phenomenon, and we discuss possible measures to diminish it.

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Section: Introductionmentioning

confidence: 99%

Harmonic lasing in x-ray free electron lasers

Schneidmiller

Yurkov

2012

Phys. Rev. ST Accel. Beams

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“…For example, an FEL that operates in harmonic lasing mode (n > 1) provides access to shorter wavelengths for fixed beam and undulator parameters [4][5][6][7][8][9]. The harmonic emission efficiency can be strongly enhanced if the fundamental wavelength is suppressed and the radiation output is dominated by one of the high harmonics [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of harmonic interaction in an undulator up to the 15th order

Xiang

Hemsing

Dunning

et al. 2013

Phys. Rev. ST Accel. Beams

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We report on experimental studies on the harmonic interaction between an optical laser and a relativistic electron beam in an undulator up to the 15th order. In this experiment, a significant energy modulation is imprinted on the beam longitudinal phase space through the electron-laser interaction when the laser frequency is the 3rd, 5th, 7th, 9th or 15th harmonic of the fundamental resonant frequency of the undulator. The experimental results are in good agreement with theory, and indicate that high harmonic interactions in undulators with large K values and small phase errors can be quite efficient. The results confirm the basic physics of harmonic interaction with a goal toward ushering forward the development of many high harmonic based applications in free-electron lasers.

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“…The relative energy spread of the electron bunch was 4.0 Â 10 À4 in the single-bunch mode, and the bunch length, which was independent of the electron-beam current below 5 mA, was approximately 90 ps (Sei et al, 2009). Dielectric multilayer mirrors having target wavelengths of 870 nm were used in the experiments (Sei et al, 2010). As shown in Fig.…”

Section: Observation Of Bunch Lengthening With a Dual Streak Cameramentioning

confidence: 99%

“…However, pioneering studies on higherharmonic FEL oscillations have made significant advances since the dawn of the development of FEL devices (Colson, 1981;Jerby & Gover, 1986). A third-harmonic FEL oscillation was achieved for the first time with a linear accelerator during the 1980s (Benson & Madey, 1989), and over the years several groups have achieved FEL oscillations on seventh or lower harmonics (Warren et al, 1990;Kato et al, 1998;Neil et al, 2001;Hajima et al, 2001;Wu et al, 2008;Sei et al, 2012a). Recently, the technique of higher-harmonic oscillation has been examined for its application in an X-ray FEL oscillator (Dai et al, 2012), which is based on an advanced energyrecovery linear accelerator and is equipped with a highreflectivity crystal in the X-ray cavity (Kim et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…We demonstrated the generation of FEL oscillations using up to the seventh harmonic (Sei et al, 2012b), which is the highest harmonic order ever achieved in the field of higher-harmonic FEL oscillations. In addition, it was demonstrated that the higher harmonic was useful for shortening the FEL wavelength using ISSN 1600-5775 the higher interference of the dielectric multilayer mirrors in the optical cavity (Sei et al, 2012c). Several aspects of the FEL gain for the higher-harmonic FEL oscillations were clarified in detail by the experiments performed with the NIJI-IV infrared FEL system (Sei et al, 2010(Sei et al, , 2014b.…”

Section: Introductionmentioning

confidence: 99%

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Electron-bunch lengthening on higher-harmonic oscillations in storage-ring free-electron lasers

Sei

Ogawa

Okuda

2017

J Synchrotron Radiat

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The influence of higher-harmonic free-electron laser (FEL) oscillations on an electron beam have been studied by measuring its bunch length at the NIJI-IV storage ring. The bunch length and the lifetime of the electron beam were measured, and were observed to have become longer owing to harmonic lasing, which is in accord with the increase of the FEL gain. It was demonstrated that the saturated FEL power could be described by the theory of bunch heating, even for the harmonic lasing. Cavity-length detuning curves were measured for the harmonic lasing, and it was found that the width of the detuning curve was proportional to a parameter that depended on the bunch length. These experimental results will be useful for developing compact resonator-type FELs by using higher harmonics in the extreme-ultraviolet and the X-ray regions.

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Third Harmonic Lasing in a Storage Ring Free-Electron Laser

Cited by 19 publications

References 18 publications

Harmonic lasing in x-ray free electron lasers

Harmonic lasing in x-ray free electron lasers

Demonstration of harmonic interaction in an undulator up to the 15th order

Electron-bunch lengthening on higher-harmonic oscillations in storage-ring free-electron lasers

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