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Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization
Published on: July 5, 2016
Digital holographic interferometer using simultaneously three lasers and a single monochrome sensor for 3D
Tonatiuh Saucedo-A1, M H De la Torre-Ibarra, F Mendoza Santoyo
1Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina con Paseo la Bufa S/N, Zacatecas, México. tsaucedo@fisica.uaz.edu.mx
Optics Express
|October 14, 2010
Summary
This study extends digital holographic interferometry for 3D measurements by using three lasers and one sensor. This method enables precise 3D displacement measurements over larger areas.
Area of Science:
- Optical Metrology
- Interferometry
- 3D Measurement Techniques
Background:
- Digital holographic interferometry (DHI) enables 3D measurements.
- Previous DHI techniques required short coherence lasers for simultaneous multi-illumination.
- Measuring large object areas with DHI was limited.
Purpose of the Study:
- To present an extended DHI technique using multiple lasers with different wavelengths.
- To enable 3D displacement measurements of large object areas.
- To utilize long coherence length lasers with a single high-resolution sensor.
Main Methods:
- Simultaneous illumination using three lasers at 458, 532, and 633 nm.
- Recording digital holographic interferograms with a single monochrome CMOS sensor.
- Isolating laser information in the Fourier spectral domain for phase difference calculation.
Main Results:
- Successfully demonstrated an extended DHI technique.
- Enabled the use of long coherence length lasers for DHI.
- Obtained orthogonal displacement components (u, v, w) during deformation.
- Measured large object areas with high resolution.
Conclusions:
- The presented DHI configuration allows for 3D displacement measurements of large objects.
- The use of multiple wavelengths and a single sensor simplifies the experimental setup.
- This technique offers a robust method for 3D metrology in various applications.
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