ABSTRACT
Historically, the first of the ‘self-terminating’ or ‘cyclic’ class of laser systems was the 723-nm atomic lead laser [1] demonstrated by Fowles and Silfvast in 1965. In 1966, Walter et al. [2] reported oscillation on the 511 and 578 nm transitions of the copper atom Cu, a system belonging to the same generic type as the Pb laser, and the one that has become the best known of the entire class. The operating principles can best be understood by reference to Figure 24.1, which shows the low-lying energy levels of atomic copper.
