3-dimensional displacements measurement with two-point source interference

Ju Yi Lee, Tzu Kuan Lin, Hung Lin Hsieh

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


An innovative double corner cube interferometer is proposed to detect the 3-dimensional linear movements as well as straightness of a linear stage. Based on the two-point source interference, two-point light sources superpose and generate an interference pattern on a specific observation plane. The interference pattern will alter accordingly when the relative position of the two light sources in space changes. This measurement system projects an expanded collimated light beam to two corner cube retroreflectors (CCR), one is fixed on the reference frame and the other is attached on the stage for measurement. The two reflected lights from the two CCRs are collected by a focal lens and produce an interference pattern on the focal plane. Then the period and direction of the interference pattern can be extract with Fast Fourier Transform (FFT) for off-axis (X-Y plane) motion measurement, and the four-step phase-shifting method is used for on-axis (Z-axis) motion measurement. The proposed measurement system can measure the three-axis displacement of the two reflectors in real-time. Different from traditional interferometry for 3D measurement which requires multiple sets of interferometers, the proposed system has the advantage to use one simple configuration and a measuring algorithm to achieve three degree-of-freedom measurements. The experiment demonstrates that the resolution for off-axis measurement is about 20 m, and on-axis measurement can reach 2 nm.

Original languageEnglish
Title of host publicationOptics and Photonics for Advanced Dimensional Metrology II
EditorsPeter J. de Groot, Richard K. Leach, Pascal Picart
ISBN (Electronic)9781510651500
StatePublished - 2022
EventOptics and Photonics for Advanced Dimensional Metrology II 2022 - Virtual, Online
Duration: 9 May 202220 May 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptics and Photonics for Advanced Dimensional Metrology II 2022
CityVirtual, Online


  • Corner cube interferometer
  • Fast Fourier Transform image analyze
  • Linear stage straightness


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