Abstract

This paper reports the UV and violet diffuse band radiation generated by two-photon pumping in Na₂ by focusing the pumping beam (~ 10 mJ) from a pulsed dye laser into a heat-pipe oven containing sodium. Measurable forward stimulated diffuse band radiation existed at 350.0-385.0 nm and 405.0-460.0 nm over the whole pumping region from 620.0 to 670.0 nm. The radiation corresponded to transitions from different high-lying triplet g states to the lowest triplet state. The signal intensity related to the pumping wavelength. The stronger signals were there where two-photon pumping was enhanced by singlet-triplet mixing levels. The weaker signals were assumed to relate to the collisions either transferring energy from the $A^{\prime }{\Sigma }_u^{+}$ to the b³Π_g state after the first photon excitation and then pumped by the second photon excitation from the b³Π_g state to a high-lying state, or were due to collisional transfer from a high-lying singlet to a nearby triplet state.

© 1986 Optical Society of America