Advances in copper laser technology: kinetic enhancement

Since their invention in 1966 copper vapour lasers (CVLs) have developed into a mature technology with applications including high-speed imaging, micro-machining, non-linear frequency conversion to the ultraviolet, and pumping of solid-state laser materials. However, the performance characteristics of conventional CVLs are fundamentally limited by kinetic processes at play within the gain medium and hence, these devices largely failed to keep pace with advances in visible solid state lasers during the late 1980s and early 1990s. In 1996 a new subclass of CVL, termed a kinetically enhanced or KE-CVL, was developed that used a ternary gas mixture (HCl–H2–Ne) to tailor the kinetic processes that limit laser performance. These devices offer dramatic improvements in power (both average and high beam quality) and repetition rate scalability. Indeed, 100 W of visible, high beam quality power is now readily available from relatively small copper laser systems. In this paper the underlying principles and performance characteristics of KE-CVLs will be reviewed.