Efficient continuous resonant frequency mixing ω4 = ω1 - ω2 + ω3 in Na2 has been realized. A bichromatic field (λ1 = 488 nm, λ2 = 525 nm), generated by an Ar+-laser-pumped Na2 Raman laser, and radiation at λ3 = 655 nm from a dye laser interact resonantly with corresponding transitions X1Σg+(υ = 3, J = 43) → B1Πu(6, 43) → X1Σg+(13, 43) → A1Σg+(24, 44) in a test Na2 heat pipe. For input powers of 200, 25, and 400 mW an output beam of as much as 0.2 mW at λ4 = 599 nm has been observed. Measured parameter dependences indicate an influence of interference effects. This is directly related to the discussion of lasing without inversion.
© 1996 Optical Society of America
S. Babin, U. Hinze, E. Tiemann, and B. Wellegehausen, "Continuous resonant four-wave mixing in double-Λ level configurations of Na2," Opt. Lett. 21, 1186-1188 (1996)