Lithium vapour excitation at 2S→3D two-photon resonance

We report study of processes which occur in lithium vapour under two-photon excitation of the Li(3D) state at 639.1 nm. A time-resolved technique has been used to measure the fluorescence from the Li(3D), Li(2P) and Li(3P) states. We have determined radiation rates for lithium atom densities in the range 1013–1014 cm−3 and laser powers (105–106 Wcm−2). The ground-state lithium atom density was determined by knowing temperature and vapour pressure in a modified heat-pipe oven. The contribution to radiation rates from different processes and prospect for cross-section determination of homonuclear reverse energy-pooling are discussed.