Storage ring two-color free-electron laser

Journal Article · 05 July 2016 · Physical Review Accelerators and Beams

DOI: https://doi.org/10.1103/PhysRevAccelBeams.19.070701 · OSTI ID:1260304

Yan, J.; Hao, H.; Li, J. Y.; Mikhailov, S. F.; Popov, V. G.; Vinokurov, N. A.; Huang, S.; Wu, J.; Günster, S.; Wu, Y. K.

Lasers operated with multiple colors have been developed over the last half century with a number of applications in physics research. For example, two optical pulses with different wavelengths but controllable time delay can be used in pump-probe spectroscopy to measure the fast dynamics of the system under investigation [1–3]. Two spatially and temporally overlapped laser beams with two colors can be employed in coherent anti-Stokes Raman spectroscopy to study molecular vibrations through nonlinear interactions with samples [4,5]. Some other applications of multicolor lasers include excited-state spectroscopy [6,7] and photomixing processes for terahertz radiation generation [8,9]. The multicolor lasers with good collinearity are particularly important in research since the laser beams of different colors can be copropagated over a long distance, collimated and focused simultaneously.The typical approach to realize simultaneousmulticolor lasing is using a dispersive or diffractive wavelength filter such as a prism or grating, either intracavity or in an external feedback cavity. Such a technology has been implemented in conventional lasers with different gain media such as dye [10–13], solid-state [14–17], semiconductor [18,19], and fiber [20–22]. However, the wavelength tunability of these lasers is limited by the bandwidth of the gain medium. Since the theoretical prediction [23] and the first experimental demonstration [24] by Madey in the 1970s, free-electron lasers (FELs) have seen great development over the past few decades, and have become increasingly attractive light sources in a number of research areas. Here, a common low-gain oscillator FEL uses an optical cavity to trap and amplify electron beam radiation. The oscillator FEL can be driven either by an electron storage ring or a linac. Oscillator FELs mainly operate in the spectral region from IR to vacuum UV. Another FEL configuration, the high-gain single-pass FEL, is mainly driven by linacs and does not use an optical cavity. In these FELs, the amplification of the FEL beam is realized in a single pass via the interaction between the electron beam and its radiation in a long undulator array [25,26] or with an external laser [27,28]. Single-pass FELs are now used as highperformance coherent light sources in the extreme UV and x-ray regimes. The natural advantages of an FEL such as its broadband gain medium (an electron beam) and the copropagation of electron and light beams make an FEL an excellent device for multicolor lasing with good wavelength tunability and collinearity. The first multicolor FEL lasing was observed experimentally on an oscillator FEL with the optical klystron configuration on the VEPP-3 storage ring [29,30]. Later on some other storage ring based FELs such as super ACO FEL [31] also reported successful multicolor FEL operations with the use of optical klystrons.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Duke Univ., Durham, NC (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-97ER41033; AC02-76SF00515
• OSTI ID: 1260304
• Alternate ID(s): OSTI ID: 1312656; OSTI ID: 1312960
• Journal Information: Physical Review Accelerators and Beams, Journal Name: Physical Review Accelerators and Beams Vol. 19 Journal Issue: 7; ISSN 2469-9888
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English