Spontaneous emission and laser mode structure at the UCSB free-electron laser

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6417660

Amir, A

Theoretical and experimental investigations of the spontaneous and laser radiation are presented. Historical overview and comparison to the early Stanford experiments are given. The theory of spontaneous undulator radiation in a waveguide FEL device, shows that the emission spectrum may differ considerably compared to the free-space result for the case of moderate waveguide aperture and electron energy. The spontaneous radiation into the different cavity modes is also calculated and used to obtain a three-dimensional form for Madey theorem. Interferometric measurements of the spectrum, confirmed the predictions of the theory. At 3 MeV electron beam energy, the laser output showed unexpected oscillation on a characteristic time scale of 5 ..mu..s and, at the same time, the laser mode swept over a discrete set of frequency modes separated by 1.3 GHz. The origin of this phenomenon is related to the accelerator terminal voltage drop during the lifetime of the pulse. The three-dimensional, small-signal FED theory is developed. A general gain expression for a diffracting optical mode interacting with an electron beam of arbitrary profile is derived and several examples including gain of a Gaussian optical mode interacting with a filamentary and cylindrical electron-beam and gain of a combination of transverse modes are discussed.

• Research Organization: California Univ., Santa Barbara (USA)
• OSTI ID: 6417660
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
43 PARTICLE ACCELERATORS
430200 -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
ACCELERATORS
BEAMS
BREMSSTRAHLUNG
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
ELECTROMAGNETS
ELECTRON BEAMS
EQUIPMENT
FREE ELECTRON LASERS
LASERS
LEPTON BEAMS
MAGNETS
ONDULATOR RADIATION
OSCILLATION MODES
PARTICLE BEAMS
RADIATIONS
WAVEGUIDES
WIGGLER MAGNETS