Influence of depolarization effects in interferometric measurement methods

Patrick Menn; Ervin Kolenovic; Wolfgang Osten; Werner P. O. Jueptner

doi:10.1117/12.445568

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23 October 2001 Influence of depolarization effects in interferometric measurement methods

Patrick Menn, Ervin Kolenovic, Wolfgang Osten, Werner P. O. Jueptner

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Proceedings Volume 4398, Optical Measurement Systems for Industrial Inspection II: Application in Industrial Design; (2001) https://doi.org/10.1117/12.445568
Event: Lasers in Metrology and Art Conservation, 2001, Munich, Germany

Abstract

The quality of interferometric measurement methods, such as fault detection by shearography, is highly influenced by the intensity distribution of the illuminating light. Usually it is intended to obtain a homogeneous object illumination while common laser light sources provide a Gaussian intensity distribution. In this paper it is investigated how the intensity distribution of the detected light is influenced by the polarization states of the incident and the scattered light. In literature usually the Stratton-Chu equation is used to describe depolarization effects. However, this equation is valid only in the Fraunhofer region, which is unsuitable for most interferometric measurements. For this reason a still unpublished general expression for the amplitude of the electromagnetic field close to the scattering surface is derived. Based on this novel formula the correlation between the intensity distribution and the polarization state of the scattered light is investigated analytically, numerically and experimentally. In the numerical part the integral formula is used to generate the light field scattered by a metal plate. As input data for the simulation the measured surface structure of a real metal plate is used. Additionally, the theoretical results are compared to measured intensity distributions for several combinations of input and output polarization states.

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Patrick Menn, Ervin Kolenovic, Wolfgang Osten, and Werner P. O. Jueptner "Influence of depolarization effects in interferometric measurement methods", Proc. SPIE 4398, Optical Measurement Systems for Industrial Inspection II: Application in Industrial Design, (23 October 2001); https://doi.org/10.1117/12.445568

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