Theoretical and Experimental Investigations on the Quasi-Optical Mode Converter for a Pulsed Terahertz Gyrotron

摘要

Theoretical and experimental investigations on the quasi-optical (QO) mode converter for a 0.42 THz, TE mode pulsed gyrotron have been carried out. The vector diffraction theory and the multiple iterative algorithms are used to design and optimize the QO mode converter, and the theoretical value for the conversion efficiency is %. The actual conversion efficiency is % by measuring the input and output power of the QO mode converter indirectly with a calorimeter. The field distribution on the output window of the QO mode converter is measured with an infrared video camera, and a well-focused Gaussian-like beam has been observed on the output window. The experimental results agree well with the theoretical predictions.