Analysis of two frequency harmonic undulator radiation and gain

The spectral properties of radiation of a relativistic electron beam in a two frequency harmonic undulator are analytically investigated. The technique of generalized Bessel function is effectively used to present some of the novel features associated with the two frequency harmonic undulator radiation. An analytical expression for gain of the two frequency harmonic undulator (TFHU) is presented for comparison with the two frequency undulator (TFU).