An apparatus and method for microwave generation and amplification by stimulated emission of radiation

Invention relates to a Josephson device for microwave generation and amplification by stimulated emission of radiation. The Josephson device comprising a resonant cavity having a resonance frequency, a Josephson junction configured for exhibiting an AC Josephson effect and is capable of having a zero voltage state and a non-zero voltage state, the Josephson junction being electromagnetically coupled to the resonant cavity. The Josephson device is configured for the microwave generation and amplification by stimulated emission of radiation with an emission frequency based on the resonance frequency of the resonant cavity at the non-zero voltage state. An advantage of the invention is that by applying the invention, generation of coherent microwave radiation with narrow linewidths at cryogenic temperatures unaffected by environmental charge noise can be achieved.