Capillary laser cathode - has auxiliary cathode in chamber with negative differential compensated for by positive auxiliary in anode circuit

摘要

Stabiliser is for a Helium-Neon gas capillary laser using d.c. glow discharge excitation. The negative differential resistance of the excitation circuit is compensated by a switched non-linear positive element in the circuit. This element is an auxiliary discharge cathode assembly in proximity to the main cathode assembly. The object is to achieve stability without using high frequency excitation circuitry. The optical axis (1) of the laser is through the capillary section (2) with a ring anode (3) at one end and the cathode (5) chamber (4) at the other. Optically transparent windows (6) are provided at each end, inclined Brewster windods, of the laser and a pressure input (7) is provided for the He-Ne gas. The auxiliary cathode (10) is located in the cathode chamber (4) and in proximity to the main cathode (5) which is on the optical axis (1).