Paper 
Title 
Page 
TUP003 
Quantum FEL II: Manyelectron Theory 
348 

 P. Kling, R. Sauerbrey
HZDR, Dresden, Germany
 R. Endrich, E.A. Giese, W.P. Schleich
Uni Ulm, Ulm, Germany



We investigate the emergence of the quantum regime of the FEL when many electrons interact simultaneously with the wiggler and the laser field. We find the Quantum FEL as the limit where only two momentum states are populated by the electrons. Moreover, we obtain exponential gainperpass and startup from vacuum.



TUP004 
Quantum FEL I: Multimode Theory 
353 

 R. Endrich, E.A. Giese, W.P. Schleich
Uni Ulm, Ulm, Germany
 P. Kling, R. Sauerbrey
HZDR, Dresden, Germany



The quantum regime of the FEL in a singlemode, singleparticle approximation is characterized by a twolevel behaviour of the centerofmass motion of the electrons. We extend this model to include all modes of the radiation field and analyze the effect of spontaneous emission. In particular, we investigate this scattering mechanism to derive experimental conditions for realizing an FEL in the quantum regime.


