The linewidth of a single 140 GHz gyrotron pulse has been measured using a time domain sampling technique. A spectral resolution of 60 kHz could be achieved, whereas the pulse length of the gyrotron did not exceed 600 μs. The paper describes the measurement set-up and preliminary results are presented.
"Linewidth measurement on a 140 GHz gyrotron", Proc. SPIE 1576, 16th International Conference on Infrared and Millimeter Waves, 15763S (1 October 1991); doi: 10.1117/12.2297849; https://doi.org/10.1117/12.2297849