Cerenkov maser and Cerenkov laser devices

Cerenkov Masers were operated over a wavelength range extending from 1 cm to just below 1 mm, and power levels of 200-250 kW in the 1 cm range were obtained. In the 1 cm range, voltage-tuning over 1 octave was achieved, and at 3 mm, a single structure was tuned from 88 to 130 GHz. At the higher power levels, gas breakdown was used as a diagnostic tool. This work was described in a number of publications and a bibliography and abstracts are attached. A flat-grating cylindrical mirror-based device (the realivistic orotron) was also examined. Power levels comparable to or greater than the best that can be obtained from mm-wavelength, coupled-cavity, travelling-wave tubes were obtained. The voltage-tuning range of these devices was also substantial. Single resonators were tuned over a half octave range, about 30 GHz, and at higher frequencies (60-80 GHz) + or - 10 percent tuning was achieved. The peak power at shorter wavelengths was 10 kW, and in the 1 cm range, 30 kW levels were obtained. The development of the mm-wavelength Cerenkov source also led to consideration of far- to near-infrared Cerenkov lasers. These were compared to the undulator type of Free-Electron lasers, and their relative advantages and disadvantages explored. A proof-of-principle far-infrared experiment has been proposed.