March 11, 2004


Gil Travish
Particle Beam Physics Laboratory

PBPL’s VISA II FEL Experiment Yields Amplified Signal with > 100nm Bandwidth

(Brookhaven, NY, 11MAR04) The VISA II Free Electron Laser (FEL) experiment lead by UCLA’s Particle Beam Physics Laboratory (PBPL) has amplified 800nm light, starting from noise, with a bandwidth of over 100nm. The VISA II experiment is a collaboration between PBPL, the University of Rome, and the ATF group at Brookhaven National Laboratory (BNL). The project set out to investigate chirped and highly compressed electron beam’s in high gain FELs. In addition to forwarding the basic science understanding of radiation production, the VISA project aims to enhance future light sources, specifically through the understanding of ultra-short pulse length production in FELs.

The VISA II project studies fundamental FEL physics and seeks to understand the production of radiation from chirped and compressed electron bunches. The VISA II project follows the successful VISA project and extends the work in three significant areas: non-linear electron beam dynamics manipulation (through the use of sextupoles and second order transport corrections); creation and transport of highly chirped (in energy) electron bunches; and, the installation and use of a magnetic chicane bunch compressor.

The large bandwidth observed along with significant amplification (gain > 106) indicates that the FEL process is not degraded by the strong energy chirp of the electron beam. This result suggests that future experiments with compressed and chirped electron beams will achieve saturation of the gain in light pulses having large bandwidth, that can be optically compressed to the femto-second time scale.

Additional information on PBPL and the VISA II Project is available at the group web site:

The Particle Beam Physics Laboratory at the UCLA Department of Physics investigates beam physics, accelerators and attendant technologies.

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