Limit of sensitivity in the detection of sodium atoms in a flame with the resonant Voigt effect

Abstract

The limit of sensitivity was investigated in the detection of sodium atoms in a flame with the resonant Voigt effect. An elliptically polarized beam of light from a cw dye laser was used to probe magnetically induced optical anisotropy of sodium atoms introduced into a propane–air flame. The optical path length in the flame was 8 mm, and the effective volume of the probed region was 1.1 × 10−9 m3. Sodium atoms of the number density of 9.5 × 1013 m−3 in the flame produced a signal-to-noise ratio of 120 when the cross-correlation technique was incorporated to estimate the signal energy relative to the background-noise energy.