1. Output power and degree of transverse coherence of X-ray free electron lasers
- Author
-
E.L. Saldin, Mikhail Yurkov, and Evgeni Schneidmiller
- Subjects
Physics ,business.industry ,Free-electron laser ,Synchrotron radiation ,Degree of coherence ,Laser ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Coherence length ,law.invention ,Optics ,law ,Physics::Accelerator Physics ,Thermal emittance ,Spontaneous emission ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Atomic physics ,business ,Coherence (physics) - Abstract
The explicit solution of the initial value problem is obtained for a SASE FEL (self-amplified spontaneous emission free electron laser) operating with a large ratio of electron beam emittance to the reduced wavelength, ϵ ˆ = 2 π ϵ / λ ≫ 1 . The output power and the degree of transverse coherence are explicitly calculated for a high-gain linear regime. The degree of coherence is shown to be dependent on the ratio of the number of FEL gain lengths to the parameter ϵ ˆ . In particular, in the multi-mode limit the radiation from a SASE FEL has by the squared number of gain lengths higher degree of transverse coherence than a synchrotron radiation generated by a beam with the same emittance. An estimate for the degree of coherence of the radiation from X-ray SASE FEL at saturation is presented.
- Published
- 2008