Lasing on a weak intercombination transition (4p(4)S(3/2)->4s(2)P(3/2)) in ArII

Argon laser lines in the violet-blue spectral region have been studied experimentally. CW generation has been achieved on a set of close lines: 438.4, 437.6, 437.1 and 436.2 nm, the 438.4 and 436.2 nm being observed for the first time. CW lasing has been also observed on 418.2 and 431.0 nm lines. The highest output appeared on the 438.4 nm line, which corresponds to weak quartet-doublet transition 4p(4)S(3/2)-4s(2)p(3/2). The measurements yielded the Einstein coefficient, branching coefficient, saturation parameter and unsaturated gain of 438.4 nm transition. The study shows the possibility of high power generation on a forbidden transition with Einstein coefficient 10(6) sec(-1), the latter being by 1-2 orders lower than for other strong laser lines.