Continuously tunable narrow-band terahertz generation with a dielectric lined waveguide driven by short electron bunches

A continuously tunable narrow-band terahertz source based on Cherenkov wakefield generation in a dielectric lined waveguide driven by short sub-picosecond electron bunches has been experimentally demonstrated. A large tunability range of 0.55–0.95 THz was achieved by implementing the waveguide design as a planar structure with variable 0.15–1.10 mm gap and thin
25
 
 
μ
m
dielectric layers. The source operates essentially in a single mode regime with higher order modes of negligible intensity. THz pulse energy was measured across the tunable range and compared with theory.