The essence of the invention is the use of supercooled superconductors for
generation of high-frequency electric oscillations. The superconductor is
supercooled, i.e. in the normal phase at a temperature lower than the
critical transition temperature for superconductivity, under an applied
electric energy source. In such non equilibrium conditions the
superconductor can have negative differential conductivity which can be
used as an active medium in generators of electric (current and voltage)
oscillations. Such generators can be used in the superconducing
electronics. Oscillation can be modulated by the change of bias voltage,
electrostatic doping by a gate electrode, or by light. When small
amplitude oscillations are stabilized near to the critical temperature
the generator can be used as a bolometer. The supercooled superconductors
can be used also as transistors and frequency mixers. The negative
differential conductivity of superconductor is created by the excess
conductivity of fluctuation Cooper pairs. This behavior is predicted by
the solution of the Boltzmann kinetic equation of the metastable in the
normal phase Cooper pairs. Boltzmann equation for fluctuation Cooper
pairs is derived as a state-of-the-art application of the microscopic
theory of superconductivity.