The frequency of a AlGaAs diode laser has been locked to the 8118-cm-1(f3d2s5M07)—20,218-cm-1 transition of UI at 826.20570 nm using the optogalvanic effect. A hollow cathode vapor generator has been utilized to produce a density of 1012 atoms/cm3 of uranium in vapor phase. The absolute frequency stability for a 10-min run was estimated to be better than 500 kHz P-P at an integration time of 1 s. This preliminary result shows that the rich optogalvanic spectrum of uranium can be efficiently used for the frequency-locking of semiconductor lasers.
Eric David and Jean-Marie Gagne, "Frequency locking of laser diode using metallic vapor optogalvanic spectrum: Ui," Appl. Opt. 29, 4489-4493 (1990)