At least one second beam of light from a first beam of light generated by a laser is directed into an atmosphere. Light therefrom scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal, which together with a reference beam from the first beam of light are simultaneously processed by an interferometer, and resulting fringe patterns are imaged onto a detector adapted to output a resulting at least one signal responsive thereto. In various aspects: a data processor gates the signal to provide a range-responsive measurement; the light signal is multiplexed; a circle-to-line interferometer optic transforms an at least partially circular fringe pattern to a substantially linear fringe pattern; or a CCD detector provides for recording a range-resolved image by successively transferring charges from one adjacent row of photosites to another.