Short Rayleigh length free electron lasers
| Autor: | William B. Colson, R. L. Armstead, P.P. Crooker, R. Vigil, T. Voughs, J. Blau, Bryant Williams |
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| Přispěvatelé: | Physics |
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Free electron model
Physics Nuclear and High Energy Physics Mode volume Physics and Astronomy (miscellaneous) business.industry Free-electron laser Surfaces and Interfaces Undulator Laser law.invention Resonator Optics law Rayleigh length Cathode ray Physics::Accelerator Physics lcsh:QC770-798 lcsh:Nuclear and particle physics. Atomic energy. Radioactivity business |
| Zdroj: | Physical Review Special Topics. Accelerators and Beams, Vol 9, Iss 3, p 030703 (2006) |
| ISSN: | 1098-4402 |
| Popis: | The article of record as published may be located at http://dx.doi.org/10.1103/PhysRevSTAB.9.030703 Conventional free electron laser (FEL) oscillators minimize the optical mode volume around the electron beam in the undulator by making the resonator Rayleigh length about one third to one half of the undulator length. This maximizes gain and beam-mode coupling. In compact configurations of highpower infrared FELs or moderate power UV FELs, the resulting optical intensity can damage the resonator mirrors. To increase the spot size and thereby reduce the optical intensity at the mirrors below the damage threshold, a shorter Rayleigh length can be used, but the FEL interaction is significantly altered. We model this interaction using a coordinate system that expands with the rapidly diffracting optical mode from the ends of the undulator to the mirrors. Simulations show that the interaction of the strongly focused optical mode with a narrow electron beam inside the undulator distorts the optical wave front so it is no longer in the fundamental Gaussian mode. The simulations are used to study how mode distortion affects the single-pass gain in weak fields, and the steady-state extraction in strong fields. The authors are grateful for the support from NAVSEA, ONR, and the JTO. |
| Databáze: | OpenAIRE |
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