Abstract: A waveguide gas laser of improved stability and efficiency resulting from novel improvements. Such improvements, including longitudinal RF excitation, unique ballasting techniques, a novel drive circuit design that is immediately responsive to defeat unstable hot spot problems, and a controlled power excitation function, result in an RF excited waveguide gas laser that substantially overcomes disadvantages of prior art devices.In one embodiment the invention consists of a longitudinally excited RF waveguide laser in which the spacing geometry of the electrodes is variable independently of the waveguide chamber geometry resulting in increased performance efficiency. In addition, hot spot problems are eliminated or substantially reduced by capacitive ballasting achieved through novel structural configurations including electrodes that are isolated from the waveguide chamber by means of a suitable dielectric spacing medium such as ceramic or aluminum oxide.