CO2 TEA laser excited by preionized discharge through a dielectric

The performance of a CO2 TEA laser with dielectric electrodes is described including primarily (1) enhancement of discharge uniformity with preionization and (2) the advantages of highly inductive discharge circuitry. The device used barium titanate electrodes with a gain volume and length of 23 cu cm and 40 cm, respectively, and has demonstrated specific extraction of 6 J/1-atm and stable operation in gas pressures above two atmospheres. These results with preionization are a significant improvement in operating characteristics compared to previous devices without preionization and demonstrate that performance equivalent to conventional metallic electrode TEA lasers can be easily obtained. Additionally, laser output energy and efficiency for constant input energy were found to increase with discharge circuit inductance (and pulse duration) giving rise to a maximum increase of 20% over the range tested. Optimum performance was achieved for a total discharge circuit inductance of about 2 microH, thereby obviating the need for very low inductance circuits common to metallic electrode devices. Other advantages of dielectric electrodes compared to metallic electrodes are presented.