POWER AND STABILITY IMPROVEMENTS IN A BLUMLEIN TYPE TEA C02 LASER

摘要

A compact transversely-excited atmospheric pressure (TEA) C02laser utilizing a Blumlein type main discharge and ladder predischargetechnique has been constructed and operated at repetition rate to100 pps under gas recirculation. First,the addition of small amountsof a seed gas (tri-n-propylamine) to a C02:N2:He gas mixtureremarkably enhanced the laser power with the aid of gas preionizationby ladder spark discharge. The optimum delay time between ladder andmain B1umlein discharges was also studied to be up to 2μsec for aCO2-N2-He gas mixture with the seed gas. It is found that UVphoto-excited N2 gas is favorab1e for Penning ionization of the seedgas. Secondly，in high-repetition-rate operation of 30 pps，gasrecirculation through a big gas tank cooled by water makes greatprogress in stabilization of the output power of a sealed-off laserover one hour; as not expected， particularly without either theaddition ofa seed gas or ladder predischarge. It is noticeable thatladder spark discharge and photo-dissociated seed gas seem veryharmful for electrodes and laser gas to strongly suppress the laserpower in a few minutes under 30 pps operation.