Wavelength dependence near a degeneracy point of lasing and 4-wave mixing processes in Na vapor

Accurate measurements were made of lasing and 4-wave mixing processes in Na-vapor inside a double heatpipe oven. Scanning Nd:YAG pumped pulsed dye laser through the two-photon resonance 3s2S1/2 → 5s2S1/2, and a high resolution double-monochromator near the 5s - 4p2P1/2,3/2 single photon resonance, we easily distinguished the two lasing multiplets due to J = 1/2 and 3/2 populations emitting blue 330 nm light. We also observed two other components. By varying the laser polarization, intensity and Na density these were determined to be parametric 4-wave mixing lines with maximum intensity for slight phase mismatch. As the dye laser was scanned, the wavelengths of the lasing and 4-wave mixing peaks shifted, each pair with its own slope, and crossed - a process providing a spectroscopic pump mechanism to populate the |MJ ≥| + 1/2 > magnetic substate of the ground state. Similar experiments are underway for other 4 wave mixing processes