Developing a long lifetime three-electrode spark-gap switch for high power, repetitive, narrow pulse width transversely excited atmospheric CO laser.

A three-electrode spark-gap switch is developed to improve the stability of breakdown discharge in a high power repetitive transversely excited atmospheric CO laser. The discharge gap is specially designed to achieve a high speed gas flow in the discharge zone. A gas circulation is applied in the switch to make the ionization gas recover quickly. The influence of gas pressure and gap spacing is numerically analyzed. During a test of 10 min (at 500 Hz, 25 J/pulse), the feasibility of the switch was proved. The electrode lifetime in this spark-gap switch is extended to more than 10 shots for high power repetitive laser output.