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Updated: Apr 6, 2026
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Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization
Published on: July 5, 2016
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Summary
Transverse digital holography, a phase-stepping speckle correlation interferometry technique, maps surface displacement for strain analysis. This method quantifies uniaxial strain, rotation, and thermal contraction, with potential for biaxial measurements.
Area of Science:
- Optical Metrology
- Materials Science
- Solid Mechanics
Background:
- Speckle correlation interferometry is a technique used for measuring surface displacement.
- Phase stepping is a crucial component for obtaining complete displacement maps.
Purpose of the Study:
- To describe the analysis of transverse displacement maps obtained via phase-stepping for surface strain calculation.
- To demonstrate the application of this technique for measuring rotation, thermal contraction, and notch-tip strains.
Main Methods:
- Utilizing transverse digital holography with phase stepping to capture surface displacement.
- Applying least-squares fitting to flat surface sections of the displacement map for strain analysis.
- Analyzing strain data to quantify uniaxial strain, rotation, and thermal contraction.
Main Results:
- Complete transverse displacement maps of object surfaces were obtained.
- Surface strain analysis was successfully performed by fitting displacement data.
- Examples demonstrated the measurement of rotation, thermal contraction, and strains around a notch tip.
Conclusions:
- Phase-stepping transverse digital holography provides a method for detailed surface strain analysis.
- The technique is effective for measuring uniaxial strain and related phenomena like thermal contraction and rotation.
- Future work could extend the method for biaxial strain measurements.
