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Improved Interferometric Optical Testing

From 4D Technology Corporation
 

 

Interferometry is used for testing optical components and optical systems as well as the metrology of many other components, such as the flatness and roughness of hard disk drive platters and the shape of magnetic recording heads and machined parts.

This article describes three recent advances that are broadening the applications of interferometric metrology: a new technique for reducing the sensitivity of interferometry to vibration; an interferometric method for measuring deformations and vibrations of diffuse surfaces; and a method for reducing the sensitivity to vibration and coherent noise and enabling measurement of parallel glass surfaces.

Before delving into these new techniques, I will first describe phase-shifting interferometry, which is critical to all three advances. Moreover, the phase shifting technique has greatly increased the popularity and the usefulness of interferometry in industrial and research applications.

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Lapmaster International - Interferometer Flatness Measuring
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Precitec, Inc. - CHRocodile Sensors
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CVI Melles Griot - Absolute™ Fizeau λ/50 Reference Spheres
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Extramet Products, LLC - Mechanical Seals
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Topics of Interest
In the testing of optical components and optical systems there are many requirements on the precision and accuracy, measurement time, ease of use, dynamic range, and environmental conditions. (Read More)
There are three types of optical strain gauges: photoelastic, Moire interferometry, and holographic interferometry. Photoelastic strain gauges subject an elastomeric material to a load and illuminate... (Read More)
3.4 Phase modulating sensors and interferometric techniques Optical interferometry is a well established technique which is associated with high resolution optical spectrometry and the precise... (Read More)
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The technique for measuring changes in diffuse surfaces using Electronic Speckle Pattern Interferometry (ESPI) is well known. We present a new electronic speckle pattern interferometer that takes... (Read More)