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

He, W. and Donaldson, C. R. and Zhang, L. and Ronald, K. and Phelps, A. D. R. and Cross, A. W. (2017) Broadband amplification of low-terahertz signals using axis-encircling electrons in a helically corrugated interaction region. Physical Review Letters, 119 (18). 184801. ISSN 0031-9007

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    Abstract

    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. The second harmonic cyclotron mode of a 55-keV, 1.5-A, axis-encircling electron beam is used to resonantly interact with a traveling TE21-like eigenwave achieving broadband amplification. The gyro-TWA demonstrates a 3-dB gain bandwidth of at least 5.5 GHz in the experimental measurement with 9 GHz predicted for a wideband drive source with a measured unsaturated output power of 3.4 kW and gain of 36–38 dB. The approach may allow a gyro-TWA to operate at 1 THz.