Shape measurements of microscopic objects using computational shear interferometry

Mostafa Agour; Claas Falldorf; Ralf B. Bergmann

doi:10.1117/12.2212910

9 March 2016 Shape measurements of microscopic objects using computational shear interferometry

Mostafa Agour, Claas Falldorf, Ralf B. Bergmann

Author Affiliations +

Proceedings Volume 9718, Quantitative Phase Imaging II; 97182M (2016) https://doi.org/10.1117/12.2212910
Event: SPIE BiOS, 2016, San Francisco, California, United States

Abstract

We present an efficient and less time consuming implementation of Computational Shear Interferometry (CoSI) by applying a smoothness on the assigned wave field. The method is used to recover the three dimensional form of a micro injection molded part from a set of shear measurements. For this purpose, six shear experiments have been recorded with the shears varying in orientation and magnitude. Varying the shears orientation and magnitude is applied using a setup consisting of a 4f filter with a reflective phase-only spatial light modulator (SLM) in the corresponding Fourier plane. The SLM is used as an electronic diffraction grating with a blazed structure. Based on the birefringent properties of the SLM two orthogonally polarized images, one diffracted and one reflected, appear on the camera sensor and produce shear interferograms. The shift between the images depends on the period and the orientation of the blazed grating. From shear interferograms, the phase of light diffracted by the object is reconstructed by CoSI. Thus the height map of the object is determined.

Conference Presentation

Citation Download Citation

Mostafa Agour, Claas Falldorf, and Ralf B. Bergmann "Shape measurements of microscopic objects using computational shear interferometry", Proc. SPIE 9718, Quantitative Phase Imaging II, 97182M (9 March 2016); https://doi.org/10.1117/12.2212910

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