High-harmonic Gyrotrons with Selective Cavities

Experimental verification of the a novel method of selectivity increase in high- harmonic gyrotrons is reported. The second-harmonic operation of a pulsed gyrotron was observed at the frequency of 1.2 THz and at very high transverse mode TE58, 13 which is, to the best of our knowledge, the highest transverse mode selectively excited in gyrotrons so far.