Evanescent light–atom interaction detected by optogalvanic effect

Abstract An evanescent light penetrating an atomic vapour near a dielectric surface could be a probe for many atom-boundary phenomena. We show the possibility of very sensitive detection of the resonant atom–light interaction near the surface by using the optogalvanic effect for an evanescent wave. We observe a narrowing of the profile of the detected atomic line, and we point out some properties of the optogalvanic effect in the evanescent wave.