Optogalvanic detection of resonant two-photon transitions from the 6 3P J excited states of Hg I

Abstract

Resonant two-photon transitions from the 6 3P J excited states of Hg I have been observed for the first time. The excited states of Hg I were generated in a low-pressure, mercury-dosed, hollow cathode discharge lamp; the two-photon transitions were stimulated using a pulsed dye laser and detected via the optogalvanic effect. Each of the three Hg I 6 3P J →7 3P J (Δ J=0; J=0, 1, 2) transitions and the Hg I 6 3P 2→8 3P 2 transition were observed. The latter transition was used as the basis of experiments to map the spatial distribution of the 6 3P 2 state in the discharge volume. Attempts to observe the two-photon excited LIF transition Hg I 8 3P 2→7 3S 1 at 690.7 nm in a hot cathode, low-pressure, mercury-argon discharge were unsuccesful.