Design Studies of Quasi-Optical Mode Converter for 105 GHz High-Power Gyrotron

In this paper, the design aspects of the quasi-optical launcher (QOL) and matching optics unit (MOU) are performed for 105 GHz gyrotron. After the interaction cavity and nonlinear taper section, high power RF wave with the cavity mode of ${\mathrm {TE_{17,6}}}$ need to be converted to Gaussian like mode which can be obtained from a dimpled wall QOL. The Gaussian content of the converted beam is achieved by 99% using commercially available launcher optimization tool (LOT) & Surf3D. Besides, design of a matching optics unit (includes a set of phase correcting mirrors) is carried out using in-house code Gyrotron Design Studio (GDS.V.1.2019) to correct the phase of the off-axis Gaussian beam.