Precise focal-length measurement technique with a reflective Fresnel-zone hologram

Brian De Boo, Jose Sasian

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


A new technique for precise focal-length measurements with a hologram is presented. This technique is widely applicable and is particularly useful for measuring large, slow lenses. In diffraction, the Fresnel-zone plate hologram emulates the reflective properties of a convex spherical mirror for use during transmission null tests of an optic by use of a phase-shifting interferometer. The hologram is written lithographically and therefore offers a higher degree of precision at a lower cost than its spherical mirror counterpart. A hologram offers the additional benefit of easy characterization by use of the same interferometer employed in examining the test optic. Better than ±0.01% precision is achieved during measurement of a 9-m focal-length lens by use of a 150-mm aperture interferometer.

Original languageEnglish (US)
Pages (from-to)3903-3909
Number of pages7
JournalApplied optics
Issue number19
StatePublished - Jan 1 2003

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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