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Optical Engineering

Determination of surface roughness of plane optical components using quasimonochromatic light source and phase shifting interferometry
Author(s): Sanjib Chatterjee; Y. Pavan Kumar
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Paper Abstract

A differential interferometric technique for the measurement of surface roughness of plane optical surfaces is proposed. A polarization Sagnac interferometer, placed in the image space of a reflection microscope system with linearly polarized, spatially coherent, quasimonochromatic incident beam illumination, splits the image-forming beam from a plane test surface (TS) into laterally sheared (LS) linear orthogonal components. The LS components interfere when brought to the same state of polarization. The optical path difference (OPD) variation along the direction of lateral shear is a measure of the slope variation on the TS. Polarization phase shifting interferometry has been applied to extract the OPD variation and thus the slope distribution, slope errors, and, subsequently, height errors. System error contribution is eliminated by combining height error data obtained for parallel sections of the TS that lie along a section of the image field parallel to the direction of lateral shear, as the TS is shifted in a direction normal to the lateral shear direction between the data capture. Results obtained for an aluminized plane polished TS are presented.

Paper Details

Date Published: 11 June 2015
PDF: 8 pages
Opt. Eng. 54(6) 064102 doi: 10.1117/1.OE.54.6.064102
Published in: Optical Engineering Volume 54, Issue 6
Show Author Affiliations
Sanjib Chatterjee, Raja Ramanna Ctr. for Advanced Technology (India)
Y. Pavan Kumar, Raja Ramanna Ctr. for Advanced Technology (India)

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