High power millimeter wave sources as atmospheric sensors

Recent developments in high-power millimeter wave sources at the Naval Research Laboratory have led to an investigation of the use of these sources as atmospheric sensors. Two different sources have been developed, a quasioptical gyrotron and a TE₁₃ mode gyrotron. The former is tunable from about 80 to 130 GHz and is capable of an average power in excess of 1 kW. Operation at the harmonic should also be possible but at reduced power. The latter is a fixed frequency source at 94 GHz and should easily be capable of average power in excess of 10 kW. The tunability of the quasi-optical gyrotron could be exploited to examine the absorption spectrum of gases with strong absorption lines in this region of tunability (for instance, ozone, CO, and N₂O) and thereby determine their average concentration over long distances. The high average power of the cavity gyrotron could lend itself to a high power atmospheric sensor radar system.