Pulsed Pre-ionization Longitudinal Discharge Diffusion Cooling Of Co <sub> 2 </ Sub> Laser Research

In recent years, the longitudinal pulsed-discharge gas lasers with diffusive cooling have received renewed interests. A compact low power pulsed laser with high repetition rate has potential importance in laser exploration, fine mechanical processing, photochemistry and so on. In this dissertation the operation mechanism of pulsed-preionization diffusive cooling CO₂, laser is studied. Pulsed preionization technology is put forward to improve the stability of discharge, decrease the operating voltage, and enhance the electro-optical efficiency. Two novel preionization technologies are presented. One is "multi-segmented coaxial pulsed-preionization ". A number of metal cirque electrodes surround equidistantly outside the glass discharge tube, acting as preionization electrodes. Another is "helical transverse-pulsed preionization ". Two comparatively parallel copper foil strips surround helically outside the glass discharge tube, acting as preionization electrodes. The two technologies produce similar results basically. In contrast to pulsed discharge without preionization, the working voltage of the laser falls about 20% and the electro-optical efficiency is improved approximately 30%.Non-selfsustained longitudinal discharge CO2 laser employing helical transverse-pulsed preionization technology is investigated for the first time. The main discharge and output power are well controlled by the pre-ionization pulser. In non-selfsustained discharge the excitation and ionization processes can be controlled separately, which is useful to optimize the E/P value of the discharge. The ballast resistance can be leaved out and the maximal electro-optical efficiency reaches 19%.This paper also presents a theoretical analyzing method for the instantaneous simulation of pulsed-preionization discharge by using Pspice software, it is favorableto the optimal design of the laser discharge circuit.Finally, based on the theoretical and experimental studies above, we bring forward two new schemes of pulsed-preionization slab CO: laser with diffusive cooling. This has important significance on further developing compact, high power, high repetition rate pulsed CO2 laser.