Cross-grating slit test with an interlacing tip-tilt alignment method

Chao Wen Liang, Chien Fu Ou

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


The phase-shifting Grating-Slit test has advantages of large measurement dynamic range when using with spatial light modulator (SLM) to generate the illuminating. But the rotary slit in the test does reduce the measuring speed and may cause measurement error if it's not aligned properly with the grating. Thus, a new modulating apparatus is proposed to replace the rotary slit used in the Grating-Slit test. In addition, a pellicle beam splitter is used to make the on-axis measurement possible and the measurement error from misalignment is greatly reduced. With a micro liquid crystal display generating and switching the direction of the illuminating grating, we can simultaneously interlace the tip-tilt direction alignments during measurement.

Original languageEnglish
Title of host publicationOptical System Alignment and Tolerancing II
StatePublished - 2008
EventOptical System Alignment and Tolerancing II - San Diego, CA, United States
Duration: 10 Aug 200811 Aug 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceOptical System Alignment and Tolerancing II
Country/TerritoryUnited States
CitySan Diego, CA


  • Cross-slit
  • Focal-plane testing
  • Phase shifting
  • Ronchi test
  • Surface profile


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