Patent ID: 8717576

Claim:
A short coherence interferometer apparatus for measuring multiple axially spaced regions of a specimen, comprising: at least one measuring beam path, through which multiple individual measuring beams are incident on the specimen, and a single reference beam path, through which reference radiation is guided, the reference beam path having a single optical path length, the reference radiation being superimposed with the individual measuring beams, and being brought into interference with the individual measuring beams; wherein the individual measuring beams are axially offset relative to one another upon incidence on the specimen by an amount which is adapted to axial spacing between the axially spaced regions, and wherein the interferometer apparatus comprises a superposition device which superimposes each of the individual measuring beams returning from the specimen with the reference radiation to cause interference; and further wherein the superposition device comprises multiple outputs, each of the multiple outputs feeding a detector, wherein the superposition device receives the same reference radiation for superposition with all of the individual measuring beams and outputs a mixture of the multiple individual measuring beams superimposed with the reference radiation at each of the multiple outputs, each mixture containing fractions of the individual measuring beam, superimposed with the reference radiation in varying phasing.