Photonic-crystal mediated charged particle beam velocity modulation and electromagnetic wave generation

We present the first experimental results of a photonic crystal (PC) structure-mediated charged particle beam velocity modulation and energy exchange. Our structure was based on two photonic lattices working at 9.532 GHz: a modulation lattice (ML) driven by a 2.5–6 W signal to velocity-modulate an electron beam of dc voltage from 15 to 30 kV and current from 50 to 150 μ A, and an excitation lattice (EL) to exchange energy with the modulated beam, similar to a two-cavity klystron. Experimental results successfully demonstrated high spectral purity from signals excited by the velocity-modulated beam in the EL, with power level in excellent agreement with conventional theories.