Short-pulse CO2 laser with long pre-pulse using double-longitudinal-discharge-tube system

Abstract

A CO2 laser with a double-longitudinal-discharge-tube system produced a short laser pulse with a long pre-pulse. The CO2 laser was constituted of two longitudinal discharge tubes with an inner diameter of 16 mm and a length of 60 cm, an optical resonator, two fast, high-voltage pulsed power supplies and a pulse generator. The discharge tube for generating the long pulse was discharged first, and then the discharge tube for generating the short pulse was discharged. The CO2 laser system combined a long laser pulse with a pulse width of 11.7 μs (FWHM) and a pulse length, from the start to the end of the pulse, of 26.9 μs and a short laser pulse with a pulse width of 224 ns (FWHM). In the discharge interval of about 40 μs, a short laser pulse with a long pre-pulse was generated. In the discharge interval of 100 μs or more, a long pulse preceded a short pulse. The peak intensity and pulse width of the short pulse part depended on the discharge interval because the short pulse part was affected by the discharge in the discharge tube for generating the long pulse.