Two-photon excitation of dense sodium vapor near the nd /sup 2/D/sub 5/2,//sub //sub 3/2/ (n = 3, 4, 5) levels: Na/sub 2/ 1 /sup 3//Sigma//sup +//sub g//yields/1 /sup 3//Sigma//sup +//sub u/ excimer emission
Stanley J. Bajic, R. N. Compton, John A. D. Stockdale +1 more
Laser excitation and ionization processes in dense (1--10 Torr) sodium vapor have been studied for laser wavelengths near the two-photon allowed nd /sup 2/D(n = 3, 4, 5) and ns /sup 2/S(n = 4, 5, 6) states. In particular, the 1 /sup 3//Sigma//sup +//sub g//yields/1 /sup 3//Sigma//sup +//sub u/ excimer emission in Na/sub 2/, predicted in 1980 by Konowalow and Julienne and observed recently by Dinev et al, was studied here in greater detail. Strong excimer emission (/similar to/30 nm) was observed for two-photon pumping to both sides of the unresolved 4D states, and weak excimer emission was seen when pumping near the 5D levels. The excimer emission exhibits a complicated pump laser profile with a pronounced ''dip'' at the 4d /sup 2/D two-photon resonance. Similarly, (2+1) photon ionization via the 3d /sup 2/D and 4d /sup 2/D states shows a dramatic decrease as the sodium density increases. These results can be attributed either to depleted 3d /sup 2/D or 4d /sup 2/D population due to stimulated electronic Raman scattering (SERS) or to the interference effects recently reported by Malcuit et al. and Krasnikov et al. and treated theoretically by Manykin and Afanas'ev and by Agarwal. It is argued thatmore » both mechanisms are operative.« less
•Dec 15, 1988•0 citations