High Harmonic Emission from Slotted rectangular gyrotron oscillators

Start oscillation conditions are considered for rectangular slotted gyrotron cavities. It is found that the addition of slots to a cavity lowers the required beam power for oscillation at high harmonics and can lead to a decrease of the start oscillation beam power as the harmonic number is increased. Previous gyrotron cavity designs have consistently shown the start oscillation beam power increasing with harmonic number. Slotted devices thus appear potentially attractive as a means of achieving millimeter wave emission.