Atomic fluorescence of sodium under continuous-wave laser excitation

The tunable continuous-wave (cw) dye laser has been shown to be capable of producing saturation conditions for sodium in an air-acetylene flame. The experimental evidence indicates that the sodium doublet is a reasonably good approximation of a two-level system. Saturation of the sodium 589.6-nm line was observed at laser spectral irradiances of 1013 erg s−1 cm−2 nm−1 and greater. Measurements of the absolute-maximum fluorescence radiance under saturation conditions have been used to measure sodium concentration profiles in air-hydrogen and air-acetylene flames with spatial resolution on the order of 0.01 cm.