Spectral interferometry apparatus, comprising an interferometer adapted to be excited by an optical source, the apparatus comprising: object optics arranged to transfer a beam from the optical source, and to a target object to produce an object beam from the target object; reference optics arranged to produce a reference beam; displacing means arranged to laterally displace at least one of the object beam and the reference beam to produce a relatively displaced object beam and a relatively displaced reference beam; wherein there is an optical path difference between the relatively displaced object beam and the relatively displaced reference beam generated in the interferometer; and optical spectrum dispersing means arranged to receive the relatively displaced object beam and the relatively displaced reference beam on at least partially different portions of the optical spectrum dispersing means due to lateral displacement of the two relatively displaced beams caused by the displacing means, and arranged to disperse the spectral content of the two displaced beams onto a reading element; wherein in use the combination of the displacing means and the optical spectrum dispersing means is arranged to create an intrinsic optical delay between the wavetrains of the two relatively displaced object beam and the relatively displaced reference beam which can be used with the optical path difference in the interferometer to generate a channelled spectrum for the optical path difference in the interferometer on the reading element; and wherein the displacing means is adapted to relatively displace the object beam and the reference beam to produce the relatively displaced object beam and the relatively displaced reference beam using one or a combination of reflection, deflection, or refraction of at least one of the object beam and the reference beam. object optics arranged to transfer a beam from the optical source, and to a target object to produce an object beam from the target object; reference optics arranged to produce a reference beam; displacing means arranged to laterally displace at least one of the object beam and the reference beam to produce a relatively displaced object beam and a relatively displaced reference beam; wherein there is an optical path difference between the relatively displaced object beam and the relatively displaced reference beam generated in the interferometer; and optical spectrum dispersing means arranged to receive the relatively displaced object beam and the relatively displaced reference beam on at least partially different portions of the optical spectrum dispersing means due to lateral displacement of the two relatively displaced beams caused by the displacing means, and arranged to disperse the spectral content of the two displaced beams onto a reading element; wherein in use the combination of the displacing means and the optical spectrum dispersing means is arranged to create an intrinsic optical delay between the wavetrains of the two relatively displaced object beam and the relatively displaced reference beam which can be used with the optical path difference in the interferometer to generate a channelled spectrum for the optical path difference in the interferometer on the reading element; and wherein the displacing means is adapted to relatively displace the object beam and the reference beam to produce the relatively displaced object beam and the relatively displaced reference beam using one or a combination of reflection, deflection, or refraction of at least one of the object beam and the reference beam.