Abstract

This paper explores methods of improving the glass machining capabilities of sealed-off, pulsed RF, slab waveguide CO₂ lasers. Such devices offer a wide range of pulse durations (τ_p), pulse repetition frequencies (PRF's) and peak powers. In quartz and soda lime glass, the 10.6 µm laser wavelength has an absorption depth of a few microns and a reflection coefficient of ~ 10% This enables rapid prototyping of inexpensive refractive micro-optics with machining rates ranging from 10 to 50 µm per shot In a preliminary study [1], we successfully machined a cylindrical refractive micro-lens using a commercially available CO₂ slab waveguide laser. Observation of the finished micro-lens indicated a need to stabilise variations in pulse energy and a requirement to reduce the patterning of the surface associated with the separation of consecutive pulses during the raster scan. Stepping in the transverse direction of the lens surface was also observed This was attributed to inadequacies in the micro-lens machining algorithm that calculated position and duration of the laser pulses, along with a lower limit to the machining rate set by the ablation threshold

© 2000 IEEE