| Paper |
Title |
Page |
| MOPPH007 |
Optical Beam Quality in Free-Electron Lasers
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21 |
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- H. Freund
SAIC, McLean
- B. Hafizi
Icarus Research, Inc., Bethesda, Maryland
- J. Penano, P. Sprangle
NRL, Washington, DC
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The mode quality of the output of free-electron lasers (FELs) is near the diffraction limit. In this paper, we analyze the optical mode quality in FELs using the M2 parameter, which is a measure of the size and divergence of the optical beam. We calculate M2 in two ways:- by a direct integration over the transverse mode structure, and
- by allowing the mode to expand beyond the wiggler and analyzing the divergence.
A numerical analysis is conducted using the MEDUSA simulation code that shows that M2, as expected, is near unity at saturation but increases with the higher order mode content if the interaction proceeds past saturation.
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