Tunable Achromatic Liquid Crystal Waveplates for Broadband Polarimetric Systems

Tunable achromatic liquid crystal waveplates are designed to overcome the inherent wavelength dependence of conventional phase retarders. By combining electrically controlled liquid crystal birefringence with achromatic optical configurations, these devices provide stable and tunable phase retardation across broad spectral ranges, enabling high-performance polarimetric and interferometric imaging systems.

(a) The structure of a nematic LC cell with anti-parallel alignment at zero voltage. (b) LC molecule and optical axes geometry. (c) Schematic of the device composed of two nematic LC cells at 90 deg to each other. The polarizers are included because they are part of the testing setup of the device. OA1 and OA2 represent the projections of the optic axes on the substrates plane.

Abstract

The wavelength dependence of conventional phase retarders presents a major limitation in broadband polarimetric imaging systems. This work demonstrates a tunable achromatic liquid crystal waveplate based on two nematic liquid crystal retarders with independently applied voltages. By exploiting the voltage-dependent dispersion of liquid crystal birefringence, the device achieves achromatic phase retardation over a wide spectral range. Both achromatic quarter-wave and half-wave operation are demonstrated using the same compact device architecture, along with electrical tunability of the achromatic operating bandwidth. This approach enables stable, broadband, and solid-state polarization control for advanced optical and polarimetric systems.

© 2014 Optical Society of America

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https://www.osapublishing.org/ol/abstract.cfm?uri=ol-39-19-5487