26 August 2008 Wide-angle nonmechanical beam steering using thin liquid crystal polarization gratings
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Proceedings Volume 7093, Advanced Wavefront Control: Methods, Devices, and Applications VI; 709302 (2008); doi: 10.1117/12.795752
Event: Optical Engineering + Applications, 2008, San Diego, California, United States
Abstract
We introduce and demonstrate a compact, nonmechanical beam steering device based on liquid Crystal (LC) Polarization Gratings (PGs). Directional control of collimated light is essential for free-space optical communications, remote sensing, and related technologies. However, current beam steering methods often require moving parts, or are limited to small angle operation, offer low optical throughput, and are constrained by size and weight. We employ multiple layers of LCPGs to achieve wide-angle (> ±40°), coarse beam steering of 1550 nm light in a remarkably thin package. LCPGs can be made in switchable or polymer materials, and possess a continuous periodic birefringence profile, that renders several compelling properties (experimentally realized): ~ 100% experimental diffraction efficiency into a single order, high polarization sensitivity, and very low scattering. Light may be controlled within and between the zero- and first-diffraction orders by the handedness of the incident light and potentially by voltage applied to the PG itself. We implement a coarse steering device with several LCPGs matched with active halfwave LC variable retarders. Here, we present the preliminary experimental results and discuss the unique capability of this wide-angle steering.
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Jihwan Kim, Chulwoo Oh, Michael J. Escuti, Lance Hosting, Steve Serati, "Wide-angle nonmechanical beam steering using thin liquid crystal polarization gratings", Proc. SPIE 7093, Advanced Wavefront Control: Methods, Devices, and Applications VI, 709302 (26 August 2008); doi: 10.1117/12.795752; https://doi.org/10.1117/12.795752
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KEYWORDS
Diffraction

Polarization

Beam steering

Liquid crystals

Transmittance

Diffraction gratings

Binary data

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