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Measuring optical phase digitally in coherent metrology systems
Kelly, Damien P.; Ryle, James P.; Zhao, Liang; Sheridan, John T.
Dimensional Optical Metrology and Inspection for Practical Applications VI, Anaheim, California, United States of America, 9 April 2017 The accurate measurement of optical phase has many applications in metrology. For biological samples, which appear transparent, the phase data provides information about the refractive index of the sample. In speckle metrology, the phase can be used to estimate stress and strains of a rough surface with high sensitivity. In this theoretical manuscript we compare and contrast the properties of two techniques for estimating the phase distribution of a wave field under the paraxial approximation: (I) A digital holographic system, and (II) An idealized phase retrieval system. Both systems use a CCD or CMOS array to measure the intensities of the wave fields that are reflected from or transmitted through the sample of interest. This introduces a numerical aspect to the problem. For the two systems above we examine how numerical calculations can limit the performance of these systems leading to a near-infinite number of possible solutions. Science Foundation Ireland Insight Research Centre
Keyword(s): Personal sensing; Speckle metrology; Phase retrieval; Holography; Statistical optics; Refractive index; Paraxial approximations; Metrology
Publication Date:
2017
Type: Other
Peer-Reviewed: Unknown
Language(s): English
Institution: University College Dublin
Publisher(s): Society of Photo-optical Instrumentation Engineers (SPIE)
First Indexed: 2019-05-11 06:28:19 Last Updated: 2019-05-11 06:28:19