A first beam of light from a laser is split by a beam splitter into a reference beam and at least one second beam of light, the latter of which is directed into an atmosphere. Light from the at least one second beam of light scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal. The at least one light signal and the reference beam are simultaneously processed by a common interferometer, and resulting fringe patterns are imaged onto a detector and processed by a data processor to determine at least one associated air data product.