Relativistic electrons-based thz sources: Principles of operation and the ENEA experience

Abstract

An introduction to the general theory of free electron sources of coherent radiation is reported. The basic mechanisms for the generation of electromagnetic waves as spontaneous emission process are described together with the more sophisticated theory of gain for the description of the stimulated process. The ENEA experience in the realisation of compact free electron sources is reported jointly with the "tricks" that allowed the Frascati group to shorten the device dimensions while maintaining important performances. © 2014 Springer Science+Business Media Dordrecht.