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Proceedings Paper

Metrology of achromatic diffractive features on chalcogenide lenses
Author(s): M. Scordato; J. Nelson; K. Schwertz; P. Mckenna; J. Bagwell
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Paper Abstract

Achromatic diffractive features on lenses are widely used in industry for color correction, however there is not a welldefined standard to quantify the performance of the lenses. One metric used to qualify a lens is the sag deviation from the nominal lens profile. Imperfections in the manufacturing of the diffractive feature may cause scattering and performance loss. This is not reflected in sag deviation measurements, therefore performance measurements are required.

There are different quantitative approaches to measuring the performance of an achromatic diffractive lens. Diffraction efficiency, a measure of optical power throughput, is a common design metric used to define the percent drop from the modulation transfer function (MTF) metric. The line spread function (LSF) shows a layout of the intensity with linear distance and an ensquared energy specification can be implemented. The MTF is a common analysis tool for assemblies and can be applied to a single element. These functional tests will be performed and compared with diffractive lenses manufactured by different tool designs.

This paper displays the results found with various instruments. Contact profilometry was used to inspect the profile of the diffractive elements, and a MTF bench was used to characterize lens performance. Included will be a discussion comparing the results of profile traces and beam profiles to expected diffraction efficiency values and the effects of manufacturing imperfections.

Paper Details

Date Published: 12 October 2015
PDF: 12 pages
Proc. SPIE 9633, Optifab 2015, 96331V (12 October 2015); doi: 10.1117/12.2197695
Show Author Affiliations
M. Scordato, Edmund Optics Inc. (United States)
J. Nelson, Edmund Optics Inc. (United States)
K. Schwertz, Edmund Optics Inc. (United States)
P. Mckenna, Edmund Optics Inc. (United States)
J. Bagwell, Edmund Optics Inc. (United States)

Published in SPIE Proceedings Vol. 9633:
Optifab 2015
Julie L. Bentley; Sebastian Stoebenau, Editor(s)

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