High-resolution spectroscopy with and frequency stabilization of a cw dye laser

Abstract

The hyperfine splittings of the Na D1 and D2 lines were investigated using a single mode cw dye laser. The light of the laser was scattered by the atoms of an atomic beam and the fluorescent light was observed as the frequency of the laser was tuned across the D lines. The Doppler width of the atomic beam was reduced to about 2.5 MHz so that the absorption width of the atoms of the beam was essentially determined by the natural width of the 32P1/2 and 32P3/2 levels, which is about 10 MHz. Since the linewidth observed for the hyperfine transitions was 30 MHz, most of the hyperfine components of the D1 and D2 lines could be resolved. In another experiment the frequency of the dye laser was locked to a hyperfine transition of the D1 line. The observed variation of the output frequency of the dye laser was less than ±1.5 MHz. In addition, the intensity of the dye laser was controlled to about 10−3, using an electro-optically variable transmission filter.