Diffractive optics calibrator: Design and construction

Wenrui Cai, Ping Zhou, Chunyu Zhao, James H. Burge

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Abstract. We present a new device, the diffractive optics calibrator, for measuring duty cycle and etching depth for computer-generated holograms (CGHs). The system scans the CGH with a collimated laser beam and collects the far-field diffraction pattern with a CCD array. The relative intensities of the various orders of diffraction are used to fit the phase shift from etching and the duty cycle of the binary pattern. The system is capable of measuring variations that cause 1-nm peakto- valley (PV) phase errors in the wavefront created by the CGH. The measurements will be used primarily for quality control CGHs, but the data can also be used to provide a lookup table for corrections that allow calibration of the lithography errors. Such calibrations may be necessary for us to achieve our goal of measuring freeform aspheric surfaces with 1-nm RMS accuracy.

Original languageEnglish (US)
Article number131380P
JournalOptical Engineering
Issue number12
StatePublished - Dec 2013


  • Computer-generated holograms
  • Duty cycle
  • Etching depth
  • Instrumentation
  • Quality control

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering(all)


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