Abstract

Copper vapour lasers (CVLs) with their high prf capability (4-24 kHz), high average power (10-100 W) and diffraction-limited beam quality offer a number of advantages for visible machining applications.¹ However, many materials (such as clear polymers) are best machined using uv laser sources such as the excimer laser, which, until recently, has been the principal laser used in uv machining applications. The uv outputs available from frequency doubling of CVLs can now be generated with good efficiency to yield multi-watt diffraction-limited output ideal for uv micromachining. Frequency doubling and sum frequency mixing of CVL outputs has been investigated extensively for the last six years; however, it is only recently that reliable, stable, and efficient conversion has been demonstrated. The recent progress has come through a greater understanding of the control of CVL beam quality and improvements in focusing geometries for the nonlinear frequency conversion process.

© 1994 IEEE