Adaptive interferometric null testing for unknown freeform optics metrology

Lei Huang, Heejoo Choi, Wenchuan Zhao, Logan R. Graves, Dae Wook Kim

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


We report an adaptive interferometric null testing method for overcoming the dynamic range limitations of conventional null testing approaches during unknown freeform optics metrology or optics manufacturing processes that require not-yet-completed surface measurements to guide the next fabrication process. In the presented adaptive method, a deformable mirror functions as an adaptable null component for an unknown optical surface. The optimal deformable mirror's shape is determined by the stochastic parallel gradient descent algorithm and controlled by a deflectometry system. An adaptive interferometric null testing setup was constructed, and its metrology data successfully demonstrated superb adaptive capability in measuring an unknown surface.

Original languageEnglish (US)
Pages (from-to)5539-5542
Number of pages4
JournalOptics letters
Issue number23
StatePublished - Dec 1 2016

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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