Optogalvanic effect as a detector for intracavity atomic absorption in a cw dye laser

It is demonstrated that the optogalvanic effect in a sodium hollow cathode discharge is a sensitive detector specific to the intracavity absorption of sodium atoms in a flame. In this feasibility study the variation of the optogalvanic signal vs the sodium concentration in the flame indicated a detection limit below 1 ng/ml. The sensitivity can be easily improved, and this technique is applicable to other atoms and Doppler-free intermodulation spectroscopic detection methods.