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Proceedings Paper

Optical Testing Of Infrared Materials And Components
Author(s): C. Brady
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Paper Abstract

The current status of in-house characterization and testing of IR materials and components is described. A range of techniques are described, which were developed largely to evaluate the ZnS produced at BAe, but are equally applicable to other materials intended for use in the 8-14μm waveband. Measurement techniques are described for determining the Transmission, Refractive Index, dn/dT, Refractive Index Homogeneity, and the Modulation Transfer Function (M.T.F). These are based around a Twyman-Green interferometer using a CO2 laser as the radiation source with the exception of the M.T.F measurement, which is done using Lateral Shearing Interferometry at the single wavelength of 10.6Am. This method is preferred to the derivation of the M.T.F from the Twyman-Green fringe pattern because of its superior resolution which allows the effects of high frequency surface patterns (e.g. tool marks on diamond turned optics) to be included in the calculation. An in-house test facility has been constructed which allows all of these measurements to be carried out on a system based around the Twyman-Green arrangement with add-on sections to accommodate the test and component under examination. Using this facility, domes as large as 200mm in diameter can be measured, as well as flat plates.

Paper Details

Date Published: 11 October 1988
PDF: 8 pages
Proc. SPIE 0916, Infrared Systems--Design and Testing, (11 October 1988); doi: 10.1117/12.945569
Show Author Affiliations
C. Brady, British Aerospace Dynamics Division (United Kingdom)

Published in SPIE Proceedings Vol. 0916:
Infrared Systems--Design and Testing
Peter R. Hall; John S. Seeley, Editor(s)

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