Detecting the presence of a target material in a scene by using a multi-aperture interferometer system having a plurality of apertures at least one of which has an adjustable optical path length, by adjusting the aperture(s) to obtain a predetermined optical path length difference among the apertures, the predetermined optical path length difference being based on a source laser wavelength and a target material wavelength, illuminating the scene with the source laser, capturing a spectral data set corresponding to an interference pattern generated in the multi-aperture interferometer system for an illuminated point source in the scene, the spectral data set containing spatially distributed spectral data, and determining whether the target material is present at the illuminated point source based on a presence of spectral data in at least one side lobe of the spectral data set.