Continuous wave (CW) output power from a gas transport laser is substantially increased by disposing a plurality of parallel cylindrically tubular cathodes in the main stream transversely of the direction of gas flow and spaced above a coextensive segmented anode in the opposite wall of the channel. Ballast resistors are connected between the cathodes, respectively, and the power supply to optimize the uniform arcless distribution of current passing between each cathode and the anode. Continuous output power greater than 3 kw is achieved with this electrode configuration.
A starter element for a high power gas transport laser having cathode and anode electrodes connected across a constant current DC power supply comprises a wire-like conductor connected in parallel with the cathode to the negative terminal of the power supply and extending between the cathode and anode parallel to the gas flow transversely of and spaced closely to the middle of the cathode. The free end of the starter element extends approximately 1 cm. beyond the downstream edge of the cathode and, when the output potential of the DC power supply is applied, causes a breakdown of the gas due to the high field strength at the starter end, producing an electrical discharge between that end and the central portion of the cathode. This induces the main electric discharge between the cathode and anode. In a laser having two or more sets of cathode-anode electrodes, a starter element for each cathode is connected to the power supply in parallel with the other starter elements through a series-connected resistor and a diode which electrically isolate the starter elements from each other.
A glow discharge device positioned upstream in a flow laser gas system supplies a continuous flow of electrons to a laser discharge region defined between planar laser electrodes to develop sufficient background electron density to permit CW or quasi CW laser operation.
An improved electrode configuration and method for the deposition of electrical energy into an electric discharge laser having a gas path transversely disposed to an optical axis and the electric field is disclosed. The electrode configuration includes a cathode, having a row of preionization electrodes with each preionization electrode typically having the configuration of a pin and power electrodes positioned downstream of and in a parallel relationship to the row of preionization electrodes wherein the power electrodes typically have a configuration of a rod, and a planar anode disposed opposite the cathode in a parallel relationship thereto, wherein the cathode and the anode define the gas path therebetween. The electrode configuration is adapted for operation without ballast resistance in the electrical circuit of the power electrodes for high electrical power deposition with high efficiency into a gas having a high pressure and a high flow rate for convective cooling to obtain a laser beam having high power. The electrode configuration provides a discharge having substantially diffuse and uniform characteristics within the discharge region.
A discharge chamber is swept at high velocity by a gas discharge which burns as a steady-field discharge between an anode extending in the direction of flow and at least three single cathodes arrayed in tandem in the direction of flow. The discharge chamber is defined transversely of the direction of flow by sidewalls, the anode forming the one first sidewall and running parallel to the plane defined by the single cathodes. To achieve a long cathode life at maximum power input, and especially to achieve sufficient cooling of the downstream single cathodes, without the need for additional technical measures and components, the second sidewall defining the discharge chamber on the side facing the single cathodes continuously varies in distance from the opposite first sidewall and the anode in the area of the single cathodes.
An electrode assembly and a D.C. glow discharge system incorporating the electrode assembly. The system is stabilized by a lower pulse repetition rate (1 KHz-5 KHz) and power (<5% of sustainer power) than that required for pulse-sustained discharge. It operates with a self-sustained discharge at lower voltage than usual due to lowered work functions, increased secondary emission and effective ionization. The pulse-stabilized discharged provides an extended stable operation suitable for high power gas lasers. A water ballasted electrode unit used therein, having individually ballasted electrode elements with discrete water resistors so formed when water flows, eliminates temporally varying spatial current fluctuations and exhibits such unique characteristics as; providing capacitive coupling for a pulse, and resistive coupling for D.C., and self-optimizing current uniformity with the operating time. The electrode unit includes electrode elements protruding into the discharge volume, enlarging the effective diameter of the electrode elements resulting in a uniform discharge. The electrode unit configuration provides a positive means for removing heat from the cathode fall region, and an economical and efficient means of manufacturing. The electrode unit structural configuration is particularly well suited for a pulse-stabilized glow discharge system and can be scaled up by a building block concept to produce super high power gas lasers. High power laser system employing the discharge principle and electrode units may be referred to as a S.O.A.P. (Self-Optimizing, Abnormal-glow, Pulse-stabilized) laser.
