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Interferometry and differently reflecting surfaces

Licence partner wanted

Especially interesting for

  • optics
  • the semiconductor industry

Assessing the optical quality of surfaces by means of a Fizeau interferometer is considerably more complex if the surfaces under test show different reflectivities. Up to now, several reference surfaces have been necessary. PTB has developed a Fizeau interferometer which makes this redundant. Now, maximum contrast can be attained regardless of the reflectivity of the sample. This is achieved by introducing a commercially available, so-called “on-axis beam splitter” which splits the light irradiated along the axis of symmetry. Sample characterization is simplified by the reduction to a two-beam interference. Finally, the increased measurement dynamics enable topography measurements also in environments affected by vibrations.


Bernhard Smandek
Department Q.3 Legal Metrology and Technology Transfer
Tel. +49(0)531 592-8303
E-Mail: bernhard.smandek(at)ptb.de