The relationship between optical guiding and the relative phase in free-electron lasers

Journal Article · Sun Dec 01 00:00:00 EST 1991 · IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States)

DOI:https://doi.org/10.1109/3.104130· OSTI ID:5834608

Freund, H P; Antonsen, Jr, T M ^[1]

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1. Science Applications International Corp., McLean, VA (United States)

In this paper the relationship between the relative phase and optical guiding in the free-electron laser is studied. The relative phase in this case is defined as the shift in the wavenumber from the vacuum value integrated over the interaction length. In terms of the optical guiding of the signal in free-electron lasers, the relative phase must be positive in order for refractive guiding of the signal to occur. The relative phase is studied from the standpoint of the linear stability analysis in both the high- and low-gain regimes, and the qualitative implications in each of these regimes of the relative phase on the refractive guiding of the signal are identical. Specifically, the relative phase is found to be negative at the low-frequency over this band until it turns positive at a frequency approximately 10% below the frequency of peak gain. Thus optical guiding is indicated over a large portion, but not all, of the gain band. A quantitative measure of the optical guiding of the signal is obtained by an analytic formulation of the guiding of the signal. This formulation is based upon a separable beam approximation in which the evolution of the signal is determined by a Green's function analysis. The specific example of interest involves the low-gain regime prior to saturation. In this case, it is shown that the analytic result is in substantial agreement with the calculation of the relative phase.

• OSTI ID: 5834608
• Journal Information: IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States), Vol. 27:12; ISSN 0018-9197
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FREE ELECTRON LASERS
CORRELATIONS
PHASE STABILITY
GUIDE TUBES
ANALYTICAL SOLUTION
CALCULATION METHODS
DESIGN
FREQUENCY CONTROL
GAIN
GREEN FUNCTION
OPTICAL PUMPING
OPTICAL SYSTEMS
QUANTUM ELECTRONICS
AMPLIFICATION
CONTROL
FUNCTIONS
LASERS
PUMPING
STABILITY
TUBES
426002* - Engineering- Lasers & Masers- (1990-)
440600 - Optical Instrumentation- (1990-)
661100 - Classical & Quantum Mechanics- (1992-)