Cherenkov free electron laser in an asymmetric dielectric liner waveguide

The small signal gain of a Cherenkov free electron laser is derived. The device consists of two different dielectric liner parallel plate waveguides driven by a cold relativistic electron beam. The results are compared with a standard Cherenkov free electron laser in a symmetric liner waveguide. It is observed that the asymmetric liner CFEL results agree well with the symmetric liner CFEL near the beam threshold but differ substantially at points far away from the beam threshold voltage.