Design, Fabrication, and Applications of Liquid Crystal Microlenses

Chen, Kexu; Hou, Yuting; Shu-qing, Chen; Yuan, Dong; Ye, Huapeng; Zhou, Guofu

doi:10.1002/adom.202100370

Cited by 15 publications

(6 citation statements)

References 161 publications

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“…15,18 Understanding how the POM color patterns of LCs correspond to a particular molecular alignment is of interest not only from a fundamental perspective, but also for development of next-generation optical and sensing devices. 19,20 One method to understand the color texture of POM images is to rely on the Michel−Levy chart, which tabulates the interference color as a function of thickness and birefringence. 21−23 That method, however, is limited to a uniform orientation of the director field and is incapable of predicting the interference color in confined geometries where the alignment exhibits large spatial variations.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The realignment of a confined LC can be triggered by altering the balance between elastic and surface energies; a minute change in the external environment can completely change the material’s appearance under POM. ,, Optical and sensing devices often rely solely on the transition between configurations that exhibit different topological defects (such as bipolar and radial) that are identifiable through the brightness profile. The substantial color changes that accompany such transitions are rarely exploited. , Understanding how the POM color patterns of LCs correspond to a particular molecular alignment is of interest not only from a fundamental perspective, but also for development of next-generation optical and sensing devices. , …”

Section: Introductionmentioning

confidence: 99%

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LCPOM: Precise Reconstruction of Polarized Optical Microscopy Images of Liquid Crystals

Chen,

Palacio-Betancur,

Norouzi

et al. 2024

Chem. Mater.

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When examined with polarized optical microscopy (POM), liquid crystals display interference colors and complex patterns that depend on the material’s microscopic orientation. That orientation can be manipulated by the application of external fields, a feature that provides the basis for applications in optical display and sensing technologies. The color patterns themselves have high information content. Traditionally, however, calculations of the optical appearance of liquid crystals have been performed by assuming that a single-wavelength light source is employed and reported on a monochromatic scale. In this work, the original Jones matrix method is extended to calculate the colored images that arise when a liquid crystal is exposed to a multiwavelength source. By accounting for the material properties, including the local orientation, the visible light spectrum, and the CIE (International Commission on Illumination) color matching functions, we demonstrate that the proposed approach produces colored POM images that are in quantitative agreement with experimental data. Results are presented for a variety of systems, including radial, bipolar, and cholesteric droplets, where results of simulations are compared with experimental images. The effects of the droplet size, topological defect structure, and droplet orientation are examined systematically. The technique introduced here generates images that can be directly compared to experiments, thereby facilitating machine learning efforts aimed at interpreting LC microscopy images and paving the way for the inverse design of materials capable of producing specific internal microstructures in response to external stimuli.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LCPOM: Precise Reconstruction of Polarized Optical Microscopy Images of Liquid Crystals

Chen,

Palacio-Betancur,

Norouzi

et al. 2024

Chem. Mater.

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show abstract

“…[13,14] Alternatively, planar optical components based on liquid crystal (LC) materials also have great potential in large-size applications, known as LC Pancharatnam-Berry Optical Elements (LCPBOE). [15][16][17][18][19][20][21][22][23] The functionalities of LCPBOE rely on the birefringent nature of LC [24][25][26] and the modulation of PB phase, also known as geometric phase. [9,[27][28][29] For an LC lens, the streamlines (tangent curves) of the LC molecular axes resemble the well-known catenary of equal strength, which imparts a continuous phase to the LC device and achieves high diffraction efficiency closing to the theoretical limit.…”

Section: Introductionmentioning

confidence: 99%

Shortening Focal Length of 100‐mm Aperture Flat Lens Based on Improved Sagnac Interferometer and Bifacial Liquid Crystal

Wen

Zhang

et al. 2023

Advanced Optical Materials

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Conventional lens technologies face great challenges in applications requiring large apertures and small f‐numbers, while a liquid crystal (LC) lens based on geometric phase is a potential solution. However, the challenge of manufacturing a large size LC flat lens with high efficiency and high phase gradient still remains. Here, an improved interferometric exposure system is proposed to acquire a large‐size vectorial optical field for photo‐alignment. Bifacial LC layers are applied to reduce the focal length while maintaining a large aperture, high diffraction efficiency, and light weight. LC layers are deposited on both sides of the substrate with the same vector system. Finally, a bifacial LC flat lens with a 10 cm diameter and 88.37% diffraction efficiency is fabricated by using optical elements smaller than 2 in., while the effective focal length is reduced from 91.5 cm to 46 cm comparing to the single side LC lens. This work demonstrates the great advantages of LC‐based flat lenses for flat optical systems with large aperture.

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“…[18][19][20][21][22][23] Other optical encryption methodologies such as physically unclonable functions (PUFs) [24][25][26] and optical double random phase encoding (DRPE) [27][28][29] often suffer from similar dilemmas. On the other hand, liquid crystals (LCs) possessing optical and dielectric anisotropy generated by facile processing routes provide an ideal platform for optical encryption devices, [30] and have been extensively used in the fields such as imaging and displays, [31,32] optical anti-counterfeiting, [33][34][35] holography, [36] augmented and virtual reality. [37] Particularly, in the polymer-stabilized-liquid-crystals (PSLCs), the low-molarmass LC molecules serve as the anisotropic matrix, and their alignment is stabilized via their elastic interaction with the embedded and polymerized mesogenic monomers.…”

Section: Introductionmentioning

confidence: 99%

Robust Optical Data Encryption by Projection‐Photoaligned Polymer‐Stabilized‐Liquid‐Crystals

Liu,

Alfarhan,

Wang

et al. 2023

Advanced Optical Materials

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The emerging Internet of Things (IoTs) invokes increasing security demands that require robust encryption or anti‐counterfeiting technologies. Albeit being acknowledged as efficacious solutions in processing elaborate graphical information via multiple degrees of freedom, optical data encryption and anti‐counterfeiting techniques are typically inept in delivering satisfactory performance without compromising the desired ease‐of‐processibility or compatibility, thus leading to the exploration of novel materials and devices that are competent. Here, a robust optical data encryption technique is demonstrated utilizing polymer‐stabilized‐liquid‐crystals (PSLCs) combined with projection photoalignment and photopatterning methods. The PSLCs possess implicit optical patterns encoded via photoalignment, as well as explicit geometries produced via photopatterning. Furthermore, the PSLCs demonstrate improved robustness against harsh chemical environments and thermal stability and can be directly deployed onto various rigid and flexible substrates. Based on this, it is demonstrated that a single PSLC is apt to carry intricate information or serve as an exclusive watermark with both implicit features and explicit geometries. Moreover, a novel, generalized design strategy is developed, for the first time, to encode intricate and exclusive information with enhanced security by spatially programming the photoalignment patterns of a pair of cascade PSLCs, which further illustrates the promising capabilities of PSLCs in optical data encryption and anti‐counterfeiting.

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Design, Fabrication, and Applications of Liquid Crystal Microlenses

Cited by 15 publications

References 161 publications

LCPOM: Precise Reconstruction of Polarized Optical Microscopy Images of Liquid Crystals

LCPOM: Precise Reconstruction of Polarized Optical Microscopy Images of Liquid Crystals

Shortening Focal Length of 100‐mm Aperture Flat Lens Based on Improved Sagnac Interferometer and Bifacial Liquid Crystal

Robust Optical Data Encryption by Projection‐Photoaligned Polymer‐Stabilized‐Liquid‐Crystals

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