Polarization‐independent and electrically tunable liquid‐crystal Fresnel lenses based on photoalignment in dye‐doped liquid crystals |
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| Authors: | Andy Ying‐Guey Fuh Ju‐Chin Chen Ko‐Ting Cheng San‐Yi Huang |
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| Affiliation: | 1. Department of Physics, Institute of Electro‐Optical Science and Engineering, and Advanced Optoelectronic Technology Center, National Cheng Kung University, Taiwan.;2. Department of Physics, National Cheng Kung University, No. 1, University Rd., Tainan 70101, Taiwan.;3. Institute of Electro‐Optical Science and Engineering, National Cheng Kung University, Taiwan. |
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| Abstract: | Abstract— This work demonstrates polarization‐independent and electrically tunable liquid‐crystal (LC) Fresnel lenses based on photoalignment in dye‐doped liquid crystals (DDLCs). The LC alignments in the adjacent odd and even zones of the LC Fresnel lens are orthogonally hybrid alignments. Those are generated by surface treatment of homeotropic and homogeneous alignment layers, and the dye‐adsorption layer onto the UV‐cured surface‐relief Fresnel zone plate. The maximum focusing efficiency (～34.14%) of the fabricated LC Fresnel lens by applying a suitable AC voltage is close to the maximal theoretical focusing efficiency of a binary phase LC Fresnel lens (～40.5%). Additionally, the focusing efficiency is polarization‐independent and electrically tunable. |
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| Keywords: | Liquid crystals Fresnel lens azo dye polymer |
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