A "virtual-interferometer" technique for surface metrology

Scott M. Jobling, Paul G. Kwiat

Research output: Contribution to journalArticlepeer-review


We demonstrate a novel technique for performing aberrationcorrected surface metrology within existing wavefront-feedback systems. Our technique uses several phase measurements to calculate phase differences that directly reveal the surface gradients of an object under test, due to orthogonal displacements of that object between measurements. We then apply a least-squares algorithm for surface reconstruction using the gradient information. This approach also removes static system aberrations, providing an absolute measurement of the surface profile. To date, we have profiled a number of test optics with 20- to 40-nm RMS error, where the accuracy is determined by the amount of angular crosstalk over the system aperture.

Original languageEnglish (US)
Pages (from-to)8772-8780
Number of pages9
JournalOptics Express
Issue number9
StatePublished - Apr 26 2010

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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