Chiral nematic liquid crystal microlenses
Abstract Nematic liquid crystals (NLCs) of achiral molecules and racemic mixtures of chiral ones form flat films and show uniform textures between circular polarizers when suspended in sub-millimeter size grids and immersed in water. On addition of chiral dopants to the liquid crystal, the films exh...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2017-05-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-017-01595-6 |
| _version_ | 1818751489765539840 |
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| author | Piotr Popov Lawrence W. Honaker Mona Mirheydari Elizabeth K. Mann Antal Jákli |
| author_facet | Piotr Popov Lawrence W. Honaker Mona Mirheydari Elizabeth K. Mann Antal Jákli |
| author_sort | Piotr Popov |
| collection | DOAJ |
| description | Abstract Nematic liquid crystals (NLCs) of achiral molecules and racemic mixtures of chiral ones form flat films and show uniform textures between circular polarizers when suspended in sub-millimeter size grids and immersed in water. On addition of chiral dopants to the liquid crystal, the films exhibit optical textures with concentric ring patterns and radial variation of the birefringence color. Both are related to a biconvex shape of the chiral liquid crystal film; the rings are due to interference. The curvature radii of the biconvex lens array are in the range of a few millimeters. This curvature leads to a radial variation of the optical axis along the plane of the film. Such a Pancharatnam-type phase lens dominates the imaging and explains the measured focal length of about one millimeter. To our knowledge, these are the first spontaneously formed Pancharatnam devices. The unwinding of the helical structure at the grid walls drives the lens shape. The relation between the lens curvature and material properties such as helical pitch, the twist elastic constant, and the interfacial tensions, is derived. This simple, novel method for spontaneously forming microlens arrays can also be used for various sensors. |
| first_indexed | 2024-12-18T04:36:23Z |
| format | Article |
| id | doaj.art-69f6183ed6a945abb4a70d18c1085315 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-18T04:36:23Z |
| publishDate | 2017-05-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-69f6183ed6a945abb4a70d18c10853152022-12-21T21:20:51ZengNature PortfolioScientific Reports2045-23222017-05-01711910.1038/s41598-017-01595-6Chiral nematic liquid crystal microlensesPiotr Popov0Lawrence W. Honaker1Mona Mirheydari2Elizabeth K. Mann3Antal Jákli4Physics Department, Kent State UniversityLiquid Crystal Institute, Kent State UniversityPhysics Department, Kent State UniversityPhysics Department, Kent State UniversityLiquid Crystal Institute, Kent State UniversityAbstract Nematic liquid crystals (NLCs) of achiral molecules and racemic mixtures of chiral ones form flat films and show uniform textures between circular polarizers when suspended in sub-millimeter size grids and immersed in water. On addition of chiral dopants to the liquid crystal, the films exhibit optical textures with concentric ring patterns and radial variation of the birefringence color. Both are related to a biconvex shape of the chiral liquid crystal film; the rings are due to interference. The curvature radii of the biconvex lens array are in the range of a few millimeters. This curvature leads to a radial variation of the optical axis along the plane of the film. Such a Pancharatnam-type phase lens dominates the imaging and explains the measured focal length of about one millimeter. To our knowledge, these are the first spontaneously formed Pancharatnam devices. The unwinding of the helical structure at the grid walls drives the lens shape. The relation between the lens curvature and material properties such as helical pitch, the twist elastic constant, and the interfacial tensions, is derived. This simple, novel method for spontaneously forming microlens arrays can also be used for various sensors.https://doi.org/10.1038/s41598-017-01595-6 |
| spellingShingle | Piotr Popov Lawrence W. Honaker Mona Mirheydari Elizabeth K. Mann Antal Jákli Chiral nematic liquid crystal microlenses Scientific Reports |
| title | Chiral nematic liquid crystal microlenses |
| title_full | Chiral nematic liquid crystal microlenses |
| title_fullStr | Chiral nematic liquid crystal microlenses |
| title_full_unstemmed | Chiral nematic liquid crystal microlenses |
| title_short | Chiral nematic liquid crystal microlenses |
| title_sort | chiral nematic liquid crystal microlenses |
| url | https://doi.org/10.1038/s41598-017-01595-6 |
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