1
|
Ferrand P, Mitov M. Extending the capabilities of vectorial ptychography to circular-polarizing materials such as cholesteric liquid crystals. OPTICS LETTERS 2023; 48:5081-5084. [PMID: 37773390 DOI: 10.1364/ol.498655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/01/2023] [Indexed: 10/01/2023]
Abstract
The problem of imaging materials with circular-polarization properties is discussed within the framework of vectorial ptychography. We demonstrate, both theoretically and numerically, that using linear polarizations to investigate such materials compromises the unicity of the solution provided by this computational method. To overcome this limitation, an improved measurement approach is proposed, which involves specific combinations of elliptical polarizations. The effectiveness of this strategy is demonstrated by numerical simulations and experimental measurements on cholesteric liquid crystal films, which possess unique polarization properties. With the help of Pauli matrices algebra, our results highlight the technique's ability to discern between the different types of circular polarizers, uniform vs. non-uniform, and determine their handedness.
Collapse
|
2
|
Meng X, Qiu X, Li G, Ye W, Lin Y, Liu X, Cai M, Wang X, Li J, He Z. Study of optical rotation generated by the twisted nematic liquid crystal film: based on circular birefringence effect. APPLIED OPTICS 2019; 58:5301-5309. [PMID: 31503629 DOI: 10.1364/ao.58.005301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/22/2019] [Indexed: 06/10/2023]
Abstract
The optical behavior of twisted nematic liquid crystals (TNLCs) is revealed through an angular scanning technique. Experimental results show that the optical rotation and degree of polarization of transmitted light are dependent on the polarization direction of incident light. The optical rotation is reciprocal, i.e., the polarization direction of incident and transmitted light can reciprocate when optical rotation is π/2. In some cases, the optical rotation is zero. The orientation of alignment layers in the TN cell can be determined from the behavior of optical rotation, which agrees with the measurement by an atomic force microscope. The experimental results are explained with the model of circularly polarized light based on the circular birefringence effect. Linearly polarized incident light is the superposition of right- and left-handed circularly polarized light. The propagation velocity of circularly polarized light in the LC is relevant to the polarization direction of incident light, so that the refractive indices of left- and right-handed circularly polarized light, n- and n+, or circular birefringence Δn(=n--n+) are not constants. As a result, when a linearly polarized light with the wavelength λ propagates through a TN cell with the cell gap l, the polarization direction of transmitted light is rotated to an angle Δθ. The optical rotation Δθ(=π(n--n+)l/λ) is dependent on the polarization direction of incident light, whereas the averaged refractive index ⟨n⟩(=(n-+n+)/2) can be independent of that. The incident light is partially linearly polarized light in our experiments, so that the degree of polarization of transmitted light varies with the polarization direction of incident light because the optical rotatory rates for the primary and secondary light beams are different.
Collapse
|
3
|
Risteen BE, Blake A, McBride MA, Rosu C, Park JO, Srinivasarao M, Russo PS, Reichmanis E. Enhanced Alignment of Water-Soluble Polythiophene Using Cellulose Nanocrystals as a Liquid Crystal Template. Biomacromolecules 2017; 18:1556-1562. [DOI: 10.1021/acs.biomac.7b00121] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bailey E. Risteen
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Alyssa Blake
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Michael A. McBride
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Cornelia Rosu
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jung Ok Park
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Mohan Srinivasarao
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Paul S. Russo
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Elsa Reichmanis
- School
of Chemical and Biomolecular Engineering, ‡School of Chemistry and Biochemistry, and §School of Materials
Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| |
Collapse
|