Apparatus for mm-wave radiation generation utilizing whispering gallery mode resonators

An apparatus for generating high frequency electromagnetic radiation comprising:

• an electron source generating a pencil electron beam, an input waveguide, a deflecting cavity resonator positioned on an axis of symmetry, having beam pipes for the electron beam to enter and exit the deflecting cavity resonator, wherein the deflecting cavity resonator is designed to support two orthogonal deflecting eigenmodes having the same input eigen-frequency, wherein the deflecting cavity resonator is coupled to the input waveguide, wherein the input waveguide couples the two orthogonal deflecting eigenmodes with a 90 degree phase difference, resulting in a rotating wave in the deflecting cavity resonator, an output waveguide, a whispering gallery mode resonator, positioned along the axis of symmetry after the deflecting cavity resonator, wherein the whispering gallery mode resonator has a guiding surface and is designed to support two orthogonal whispering gallery eigenmodes having the same output eigenfrequency, wherein the whispering gallery mode resonator is coupled to the output waveguide, wherein the output waveguide is designed to couple the two orthogonal whispering gallery eigenmodes with a 90 degree phase difference, resulting in a rotating wave in the whispering gallery mode resonator, the rotating wave in the deflecting cavity resonator having the phase velocity as the rotating wave in the whispering gallery mode resonator, an electron beam source designed to produce an initially continuous electron beam, initially travelling on the axis of symmetry, through the deflecting cavity resonator.