Simulation and Analysis for a Laser-Modulated Vacuum Photodiode Terahertz Radiation Source

Vacuum electron terahertz (THz) radiation sources face great challenges in achieving fast response and continuously tunable electron emission. In this paper, a continuous wave (CW) laser-modulated vacuum photodiode terahertz radiation source is simulated by using the multiphysics simulation software COMSOL. The entire physical process of this kind of novel device is simulated, including the generation of the photoelectrons, the diffusion and drift of the electrons, the emission of the electrons, the transportation of the electron in the vacuum channel, and the collection of the electrons by the anode. The simulation method of this novel terahertz radiation source presented in this paper is useful for guiding the design and engineering implementation of this kind of device.