Studies on the Optogalvanic Effect and Isotope-Selective Excitation of Ytterbium in a Hollow Cathode Discharge Lamp Using a Pulsed Dye Laser

This paper presents studies on the pulsed optogalvanic effect and isotope-selective excitation of Yb 555.648 nm (0 cm(-1) -> 17 992.007 cm(-1)) and 581.067 nm (17 992.007 cm(-1) -> 35 196.98 cm(-1)) transitions, in a Yb/Ne hollow cathode lamp. The Yb atoms were excited by narrow linewidth (500-1000 MHz) Rh110 and Rh6G dye based pulsed lasers. Optogalvanic signal inversion for ground state transition at 555.648 nm was observed beyond a hollow cathode discharge current of 8.5 mA, in contrast to normal optogalvanic signal at 581.067 nm up to maximum current of 14 mA. The isotope-selective excitation studies of Yb were carried out by recording Doppler limited optogalvanic signals as a function of dye laser wavelength. For the 581.067 am transition, three even isotopes, Yb-172, Yb-174, and Yb-176, and one odd isotope, Yb-171, were clearly resolved. These data were compared with selective isotope excitation by 10 MHz linewidth continuous-wave dye laser. For 555.648 am transition, isotopes were not clearly resolved, although isotope peaks of low modulation were observed.