A Thz Source By Up-Converting Radio Frequency With Plasma Waveguide

The discharged frequency of a radio frequency (rf) cavity is independent of its charging source frequency and defined only by its geometry. If the dimension of a cavity could be effectively changed during its discharging state, it will emit electromagnetic energy at a different frequency than its charging source frequency. By treating the plasma as a conductor wall, we simulated the process to generate a tunable terahertz (THz) source by putting a hollow conductor wall in an rf cavity. We found that the rf energy trapped inside the "plasma wall" will be effectively converted to a higher frequency electromagnetic wave, whose parameters are determined by the radius, thickness, and density of the wall. Computer simulations have been used to study this process in detail. The study confirms that THz could emit from a discharged rf cavity by properly setting the plasma parameters. It has a great potential to develop a table-top THz source with the technology. Besides, the source will have tunability in phase, amplitude, pulse length, and frequency, which was very desired in many applications and hard to realize. (C) 2014 AIP Publishing LLC.