Operation of a quasi-optical gyrotron with a Gaussian output coupler

Abstract

The operation of a 92 GHz quasi-optical gyrotron having a resonator formed by a spherical mirror and a diffraction grating placed in −1 order Littrow mount is presented. A power of 150 kW with a Gaussian output pattern was measured. The Gaussian content in the output was 98% with less than 1% of depolarization. By optimizing the magnetic field at fixed frequency, a maximum efficiency of 15% was reached.

Multimirror quasi-cylindrical cavity resonators for frequency-tunable gyrotrons

“…It is known that the two-mirror systems, which have already been considered as possible candidates for the role of the cavities in frequency-tunable gyrotrons [12][13][14], have a fairly significant disadvantage which, in particular, restricts their wide application in practice. The nonoptimal transverse structure of the high-frequency (HF) field in such cavities stipulates a noticeable decrease in the generation efficiency and a significant increase in the starting and operating currents.…”

Smooth wideband tuning of the operating frequency of a gyrotron

“…Smooth tuning of the output-radiation frequency in a relatively wide band by varying the magnetic field is possible in gyrotrons with cone-shaped cavities due to excitation of oscillations in different sections of the cavity with a sufficiently long section of the uniform magnetic field [6], or in gyrotrons with doublemirror cavities by changing the intermirror distance [7][8][9]. However, the use of such gyrotrons has not yet become common since in the former case, the selective properties of the cavity worsen, while in the latter case, the oscillator efficiency is relatively low.…”

Low-voltage infrared free-electron lasers based on gyrotron-powered RF wigglers

“…Stable second-harmonic operation requires suppression of the fundamental cyclotron harmonic interaction. This may be achieved by replacing the upper mirror of the vertical resonator leg with a diffraction grating placed in the Littrow position [31]. Alternatively, the QOG could be operated at the fundamental cyclotron harmonic by increasing the magnetic field to 84 kG, achievable by using a niobium-tin superconducting magnet.…”