Abstract-Broadband amplification of low-terahertz signals using axis-encircling electrons in a helically corrugated interaction region

W. He, C. R. Donaldson, L. Zhang, K. Ronald, A. D. R. Phelps,  A. W. Cross,

https://journals.aps.org/prl/accepted/aa075Y48Q3c13a6851270ff5428f8a399615110c3


Experimental results are presented of a broadband, high power, gyrotron traveling wave amplifier (gyro-TWA) operating in the 75-110 GHz frequency band and based on a helically corrugated interaction region (HCIR). The second harmonic cyclotron mode of a 55 keV, 1.2 A, axis-encircling electron beam generated from a cusp electron gun was used to resonantly interact with a traveling TE21-like eigenwave, existing in the HCIR, achieving broadband amplification based on the cyclotron resonance maser instability. The gyro-TWA was measured to generate a maximum power of 3.4 kW with an unsaturated gain of 36-38 dB in the driving frequency band of 91-96.5 GHz.