Apparatus for optically analyzing an object (400) having a plurality of layers, without needing to use a reference mirror, the apparatus comprising: an extended broadband light source (200) configured to illuminate the object (400)； a spectral imager (100)； and an optical imaging system (300) configured, for a point of the object, to gather light that is reflected from the plurality of layers of the object (400) at the point into a conjugate point in the spectral imager (100), to thereby generate interference between light reflected from the plurality of layers of the object (400) at the point of the object, the spectral imager (100) being configured to analyze the interference pattern to thereby determine the thicknesses of the layers of the object (400) at the point of the object.
