The present invention may be used in the field of microelectronics, in medicine as well as in the production of lighting appliances. The method and the device of the present invention are used for increasing the brightness of optical radiation sources powered by low-voltage power supplies. The optical radiation is generated by emitting electrons and by exciting the radiation. The electrons are generated by emitting the same from the surface of a cathode, while the excitation of the radiation involves accelerating the electrons in the gaseous interval up to an energy exceeding the excitation energy of the radiating levels of the gas. To this end, a voltage is applied between the cathode and the anode, wherein said voltage does not exceed the ignition voltage of a self-maintained discharge. The device of the present invention comprises a chamber as well as electrodes having surfaces which are transparent to the radiation. The gas pressure inside the chamber is determined from balance conditions between the energetic length of an electron trip and the distance between said electrodes.