Electron Cyclotron Emission with Helical Wavefront in Millimeter Wave Regime

Recently it has been shown that the radiation from a charged particle in spiral motion has a helical wavefront. Although the cyclotron emission exists universally in nature, the vortex property has not been featured because this property is normally canceled out due to the randomness in the gyro-phase of electrons. In order to generate the ECE with helical wavefront from multi-electron in cyclotron motion, we are developing a method to control the gyro-phase by the high power Right Handed Circularly Polarized (RHCP) wave. The electrons which have cyclotron motion around the magnetic field can be phase-matched by interaction with the external RHCP wave. The coherent radiation can be obtained from these phase matched electrons.