Compact Uniform Field Electrode Profiles

In order to obtain high output powers from transversely excited pulsed lasers it is important to have a very uniform energy loading of the active gas medium. That is why there is a need for specially contoured electrodes which produce a very uniform field strength over a certain amount o f surface. A number o f authors have given solutions to this problem. Up to now, Rogowski profiles [ 1] are most commonly used, but have the serious disadvantage that three smooth segments have to be joint together in an undefined and rough manner. The best profiles are made by using the analytic formulas derived by Chang [2]. For a realistic Chang profde, however, the width of a TEA laser electrode, required to produce a square discharge, amounts to approximately 3.5 times the discharge width [3]. For some applications, however, it is desirable to have a smaller electrode-to-discharge width ratio. This is, for instance, the case for large aperture CO 2 or CO lasers, where the distance of the UV source from the electrode centre is an important measure, or for large aperture UV lasers, where the electrode inductance contributes significantly to the total circuit inductance. Compacting the electrodes in the way Chang describes in his paper is undesirable because that leads to a decrease in the field strength uniformity at the electrode surface. That is why we looked for compacting in a different way. We start with the same conformal transformation as used by Chang: