title: Adaptive interferometric null testing for unknown freeform optics metrology.
abstract: 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.
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Heejoo
authors.initials: H
authors.lastname: Choi
authors.forename: Wenchuan
authors.initials: W
authors.lastname: Zhao
authors.forename: Logan R
authors.initials: LR
authors.lastname: Graves
authors.forename: Dae Wook
authors.initials: DW
authors.lastname: Kim