Optical inspection of liquid crystal variable retarder inhomogeneities



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Quiroga Mellado, Juan Antonio and Uribe Patarroyo, Néstor R. and Vargas Balbuena, Javier and Álvarez Herrero, Alberto and Belenguer Dávila, Tomás (2010) Optical inspection of liquid crystal variable retarder inhomogeneities. Applied Optics, 49 (4). pp. 568-574. ISSN 1559-128X

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Official URL: http://dx.doi.org/10.1364/AO.49.000568


Liquid crystal variable retarders (LCVRs) are starting to be widely used in optical systems because of their capacity to provide a controlled variable optical retardance between two orthogonal components of incident polarized light or to introduce a known phase shifting (PS) between coherent waves, both by means of an applied voltage. Typically, the retardance or PS introduced by an LCVR is not homogeneous across the aperture. On the one hand, the LCVR glass substrates present a global bend that causes an overall variation of the retardance or PS. On the other hand, in the manufacturing process of an LCVR, there sometimes appears a set of micro-air bubbles that causes local retardance or PS inhomogeneities. In this work, we present an interferometric technique based on a Mach-Zehnder interferometer that is insensitive to vibrations and capable of inspecting and characterizing the LCVR's retardance or PS inhomogeneities. The feasibility of the proposed method is demonstrated in the experimental results, where the LCVR retardance is measured with an error of about 0:2 rad. The thickness of possible micro-air bubbles is obtained with a resolution of about 50 nm.

Item Type:Article
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This paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
We thank the European Space Agency for economic support of this work given by the “Validation of liquid crystal variable retarders for solar orbiter polarization modulation package” project, reference number 22334/09/NL/SFe.

Uncontrolled Keywords:Interferometry, Polarimeter, Modulators, Extraction, System
Subjects:Sciences > Physics > Optics
ID Code:22800
Deposited On:16 Sep 2013 11:47
Last Modified:28 Apr 2022 18:09

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