Abstract

Modern planar waveguide CO₂ lasers produce pulses as short as 50 µs at high average power at 1 to 2 kHz pulse rates, from sealed-off devices without gas flow. The much older TEA CO₂ lasers readily produce sub-microsecond pulses, but usually require a complex gas flow system to achieve high average power However, many materials processing tasks such as surface treatment and micro-machining benefit from laser pulse properties intermediate between these two technologies. Using pulse widths between 1 and 20 µs and materials which are strongly absorbing at the 10.6 µm wavelength, the penetration depth of heating can be minimised whilst avoiding the severe plasma screening effects associated with sub-microsecond irradiation. We present development of the RF excited planar waveguide technology to produce sealed-off, static gas sources for this intermediate processing window.

© 2000 IEEE