Solid-state cyclotron maser

A solid-state cyclotron maser, receiving a negative bias voltage and being exposed to an applied magnetic field, for generating low-power signals in the submillimeter frequency range, comprising:

• an accelerating region, a drift region, and a metal grid therebetween,
• said accelerating region and said drift region being formed from a semiconductor material having non-parabolic energy bands,
• said drift region having front and back sides which are separated by a thickness t, t being of the order of one mean-free path for electrons in the semiconductor material,
• said drift region having an outer surface which is coated with metal, said metal being at ground potential,
• said front side of said drift region having a first opening in said metal, said first opening being shaped and located such that electrons couple most strongly with radio frequency fields of the drift region,
• said back side of said drift region having a second opening in said metal, said second opening being located for coupling most strongly with the radio frequency fields of the drift region,
• said metal grid being coupled to the opening on the front side of said drift region, said metal grid forming an ohmic contact between said accelerating region and said drift region,
• said accelerating region having front and back sides which are separated by a thickness s, s being large enough to allow electrons to be accelerated to a velocity that is required for producing energy, the energy being sufficient to sustain RF oscillations, said front side being coated with a metal for forming an ohmic contact, the back side of the accelerating region covering the opening on the front side of said drift region,
• the negative bias voltage being applied to the front side of said accelerating region for accelerating electrons in the accelerating region, said electrons moving through said grid and drift region, said magnetic field being applied at an angle to the axis of said drift region for causing the electrons to propagate in helical trajectories around lines of the magnetic field and through said drift region, said electrons bunching in phase in said drift region and radiating coherently, said radiation being coupled out of said drift region at said second opening on the back side of said drift region.