The Limiting Possibilities of Miniaturization of Open-Resonator Mirrors

Using the representation of the field of a quasioptical beam in the form of expansion over plane waves, we derive an expression determining the minimum possible size of mirrors of an open resonator (OR) in which the lowest mode with small energy losses exists. To verify the obtained expression, we study experimentally the field distribution in a semisymmetric OR using the probe method. In this case, the diameter of the scattering probe was chosen on the basis of the equation derived. The difference between the measured and calculated field distributions was smaller than 8%. It is shown that the diameter of the field spot on the OR mirrors cannot be smaller than the wavelength of a microwave oscillator. The attempts to focus a Gaussian beam to a size smaller than the wavelength lead to an increase in the diameter of the field spot.     

Electric field in cathode layer of anomalous glow discharge

The cathode layer of anomalous glow discharge is calculated taking into account in a kinetic approximation the resonance charge transfer of ions emitted by the negative-glow plasma. The results of calculation of the electric-field distribution are in good agreement with experiment for a discharge potential in the kilovolt range.Kiev Polytechnic Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, Nos. 3, 4, pp. 363–367, March–April, 1992.