Abstract
We propose a novel method for producing a short pulse from a VHF-discharge-excitation slab-type CO2 laser using a halved confocal of an unstable concave and convex resonator. This method utilizes a full reflection concave mirror with a function of variable curvature, which can be controlled using a piezo electric device (PZT). Generally, slab-type lasers are modulated directly by varying pulse voltage; however, there is a fluctuation of plasma at the transition of the kHz pulsation. Consequently, the repetitive frequency is less than 10 kHz. On the other hand, the pulse oscillation with our method has a short pulse width of 300 ns and a maximum repetitive frequency of about 58 kHz. The peak power at the pulse oscillation is about 12 times as high as that of the CW oscillation.
