Multi-order lasing with a modified wiggler
- Institute of Laser Technology, Osaka (Japan); and others
A novel wiggler for multi-order harmonic lasing has been developed at ILT/ILE. This wiggler, called modified wiggler, produces a composite magnetic field that is expanded as a sum of harmonics of a fundamental field component: B(z) = B{sub 1} sin(k{sub 1}z) + B{sub 3} sin(3k{sub 1}z) + B{sub 5} sin(5k{sub 1}z) +{hor_ellipsis}, where k{sub 1} is the wavenumber of the fundamental field component and B{sub n} is the magnetic flux of nth order field component. Analytical work predicted the improvement of the gain on FEL harmonics with the modified wiggler. This effect on the gain is remarkable for the higher order harmonics, so that fifth or higher order harmonic lasing will be possible. We constructed a modified wiggler by arranging high-permeability shims inside the gap of a conventional wiggler of 20 mm period. This modified wiggler has a ratio of the third-harmonic flux to the fundamental, B{sub 3}/B{sub 1}, of 10 %, which is enough to increase the gain on the FEL harmonics. The harmonic lasing experiment is now under way using a 9 MeV S-band photo-injector at ILT/ILE. Then the wavelength is 15 {mu}m at third-harmonic and 10 {mu}m at fifth-harmonic. The gain on the third-harmonic is calculated to be 27%, which is 1.5 times greater than that of non-modified wiggler. The fifth-harmonic lasing is seeded by a CO{sub 2} laser. We will discuss about the gain enhancement as a function of modification ratio.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- OSTI ID:
- 238786
- Report Number(s):
- BNL-61982-Absts.; CONF-9508156-Absts.; ON: DE96002729; TRN: 96:013275
- Resource Relation:
- Journal Volume: 375; Journal Issue: 1-3; Conference: 17. international free electron laser conference, New York, NY (United States), 21-25 Aug 1995; Other Information: PBD: [1995]; Related Information: Is Part Of 17th international free electron laser conference and 2nd international FEL users` workshop. Program and abstracts; PB: 300 p.
- Country of Publication:
- United States
- Language:
- English
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