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Liquid-Crystal-Mediated Active Waveguides toward Programmable Integrated Optics
摘要： Optics, playing an ever-important role in life, is developing toward miniaturization and integration. Particularly, the field programming of integrated optics will benefit its functionality and durability, thus is highly pursued. Here, through precisely controlling the space-variant orientations of anisotropic liquid crystals (LCs), various graded-index waveguides are demonstrated in a homogeneous medium. Straight/bending waveguides and ring resonators are fabricated via LC photopatterning. They exhibit pronounced polychromatic light-guiding performance. Thanks to their intrinsic external-stimuli responsivity, the thermal switchability and polarization tunability are verified. By selectively polymerizing, robust functional components and active connecting waveguides can be realized on the same chip. It provides a practical and universal solution to programmable integrated optics, and extends the applications of microstructured soft matter even in wearable photonics.
关键词： integrated optics,photoalignment,waveguides,liquid crystals
更新于2025-09-23 15:19:57
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Size-Dependent Thermo- and Photoresponsive Plasmonic Properties of Liquid Crystalline Gold Nanoparticles
摘要： Achieving remotely controlled, reversibly reconfigurable assemblies of plasmonic nanoparticles is a prerequisite for the development of future photonic technologies. Here, we obtained a series of gold-nanoparticle-based materials which exhibit long-range order, and which are controlled with light or thermal stimuli. The influence of the metallic core size and organic shell composition on the switchability is considered, with emphasis on achieving light-responsive behavior at room temperature and high yield production of nanoparticles. The latter translates to a wide size distribution of metallic cores but does not prevent their assembly into various, switchable 3D and 2D long-range ordered structures. These results provide clear guidelines as to the impact of size, size distribution, and organic shell composition on self-assembly, thus enhancing the smart design process of multi-responsive nanomaterials in a condensed state, hardly attainable by other self-assembly methods which usually require solvents.
关键词： nanoparticles,photoresponsive materials,self-assembly,liquid crystals,surface plasmon resonance
更新于2025-09-23 15:19:57
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Tunable Microlasers Modulated by Intracavity Spherical Confinement with Chiral Liquid Crystal
摘要： Manipulation of laser emission offers promising opportunities for the generation of new spatial dimensions and applications, particularly in nanophotonics, super-resolution imaging, and data transfer devices. However, the ability to control laser modes and wavelength in a microcavity remains challenging. Here, a novel approach is demonstrated to control laser modes by manipulating the 3D-optical confinement, chirality, and orientations in a Fabry?Pérot microcavity with cholesteric liquid crystal droplets. Different configurations of intracavity micro-/nanostructures generate versatile dimensions of laser modes, while the significantly reduced laser mode volume further leads to single-mode lasing. Theoretical analysis is carried out to support this interesting discovery. Finally, switchable lasing wavelength with various surface anchoring forces and pH interactions is demonstrated. This novel concept not only provides a simple yet highly versatile method to manipulate laser emissions, but deepens insight into how molecules interact with and modulate laser light, laying the foundation for the development of tunable photonic devices at the molecular level. Promising applications include highly selective laser devices, laser-emission imaging, and bioinspired sensing.
关键词： tunable lasing,high-order laser mode,cholesteric liquid crystals,spherical confinement,intracavity interactions
更新于2025-09-23 15:19:57
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Liquid-Crystal Phase Optimization Using the Alignment Relay Technique for the Deposition of Single-Walled Carbon Nanotubes
摘要： The alignment and sorting of carbon nanotubes constitutes a challenging and industrially significant field of research. We have recently created a technique to simultaneously align and sort single-walled carbon nanotubes on a surface through the use of a specially designed organic thin film. This alignment relay technique can be intelligently altered to judiciously target key parameters of nanotube deposition including density, alignment, and length. Here, we demonstrate that by simply altering the nature of the liquid crystal used the average length of the nanotubes can be decreased by half while increasing the density 3-fold, with minimal impact on the diameter sorting.
关键词： liquid crystals,molecular chemistry,iptycenes,surface chemistry,carbon nanotubes
更新于2025-09-23 15:19:57
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Birefringent lighta??shaping films for minia??LED backlights
摘要： Birefringent light-shaping films (BLSFs) for mini-LED backlit liquid crystal displays (LCDs) are proposed and experimentally demonstrated by passive polymer-dispersed liquid crystal (PDLC) films. Such films show angle-selective scattering properties, achieved by proper material engineering and good vertical alignment of liquid crystals. They only respond to angles rather than spatial locations. By directly adhering the BLSF onto a LED, the angular intensity distribution of light can be tailored from Lambertian-like to batwing-like. Further simulation proves that by engineering the angular distribution, a fewer number of LEDs or equivalently a shorter light-spreading distance is required to maintain good uniformity. These BLSFs are expected to find widespread applications in emerging mini-LED backlit LCDs and shed light on designing other light-shaping films in the future.
关键词： birefringent light-shaping films,polymer-dispersed liquid crystals,angle-selective scattering,mini-LED backlights
更新于2025-09-23 15:19:57
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A Thina??Film Flexible Defecta??Mode Laser
摘要： Laser emission from a flexible defect-mode structure consisting of two photopolymerized liquid crystal thin films separated by a dye-doped polymethylmethacrylate defect layer is demonstrated. A simple and cost-effective film transfer technique is used to fabricate the flexible laser and the corresponding laser emission characteristics, which shows single-mode laser emission at λ = 582 nm, with an excitation threshold of Eth = 12.3 ± 0.5 μJ cm?2 per pulse and a slope efficiency of ηs = 6.0 ± 0.3%, are presented. The polarization state of the laser emission are also presented and are compared with the findings reported in the literature. Finally, laser-beam steering is demonstrated up to 42° by subjecting the device to a mechanically induced deformation that creates a radius of curvature of 5 mm, which is of potential interest for conformable and wearable technology platforms.
关键词： thin-film lasers,liquid crystals,flexible lasers,defect-mode lasers
更新于2025-09-23 15:19:57
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Advances in Colloid Science || Pretransitional Behavior and Dynamics in Liquid Crystal–Based Nanocolloids
摘要： The impact of nanoparticles on phase transitions in liquid crystal (LC)—nanoparticle nanocollids is still little known. This contribution results for dodecylcyanobiphenyl(12CB), pentylcyanobiphenyl (5CB), and hexyl isothiocyanatobiphenyl (6BT) as the LC host with the addition of BaTiO3 barium titanate barium titanate nanoparticles. The latter has a strong impact on the value of dielectric constant, relaxation time, and the discontinuity of the isotropic–mesophase transitions. The first-ever high-pressure studies in such systems are also presented.
关键词： dielectric constant,liquid crystals,nanocolloids
更新于2025-09-23 15:19:57
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Estimating physical properties from liquid crystal textures via machine learning and complexity-entropy methods
摘要： Imaging techniques are essential tools for inquiring a number of properties from different materials. Liquid crystals are often investigated via optical and image processing methods. In spite of that, considerably less attention has been paid to the problem of extracting physical properties of liquid crystals directly from textures images of these materials. Here we present an approach that combines two physics-inspired image quantifiers (permutation entropy and statistical complexity) with machine learning techniques for extracting physical properties of nematic and cholesteric liquid crystals directly from their textures images. We demonstrate the usefulness and accuracy of our approach in a series of applications involving simulated and experimental textures, in which physical properties of these materials (namely: average order parameter, sample temperature, and cholesteric pitch length) are predicted with significant precision. Finally, we believe our approach can be useful in more complex liquid crystal experiments as well as for probing physical properties of other materials that are investigated via imaging techniques.
关键词： machine learning,physical properties,image analysis,complexity-entropy methods,liquid crystals
更新于2025-09-19 17:15:36
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Effect of molecular structure and temperature on the helical pitch and handedness in Antiferroelectric liquid crystalline phase
摘要： Different homologous series of compounds forming antiferroelectric liquid crystalline phase were compared to obtain the information about their helical pitch and helix twist sense and how these parameters change upon temperature. Different parts of molecular structure were analysed: the structure of rigid core (presence and position of COO group), structure of non-chiral chain (fluorination of the terminal part of alkyl chain and its length, length of oligomethylene spacer, type of linking groups), structure of chiral chain (the length of chiral chain and the position of substitution). The change of the oligomethylene spacer length in the non-chiral alkyl chain causes the biggest changes in temperature dependence of helical pitch and helix twist sense. The increase of the length of this spacer causes the change of handedness of the macroscopic helical structure from right-handed to left-handed. Some compounds can be found with helix twist sense inversion within one phase.
关键词： antiferroelectric phase,liquid crystals,helical pitch,helix twist sense inversion.
更新于2025-09-19 17:15:36
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Polymeric fibers and microporous films by photo-crosslinking of triphenylene-derived liquid crystals
摘要： Two series of photoreactive discotic liquid crystals consisting of a triphenylene core and six cinnamate units with one (TPC1n) or two (TPC2n) n-alkoxy groups (CnH2n+1O; n = 10–14), respectively, as peripheral groups are synthesized. Both of them are polymerized into ?bers up to 2 mm long by UV irradiation in liquid paraf?n in the columnar LC temperature ranges. The ?ber structures seem to be preconstructed in liquid paraf?n. In addition, TPC2n are shown to form microporous ?lms up to 15 μm in diameter by simply casting the solutions of some solvents followed by drying for several minutes in air at room temperature. Photoirradiation of the ?lms in the LC temperature range converts them to polymeric ones while preserving the microporous and hexagonally ordered structure. From comparison with TPC1n and the hydrogenated derivative of TPC212, the porous ?lm-forming property is suggested to result from the combination of the double bond of the cinnamoyl group and the two long alkoxy chains on the phenyl ring.
关键词： microporous ?lm,cinnamate,self-assembly,photo-crosslinking,structure-property relations,photopolymerization,triphenylene-derived liquid crystals,?ber,membranes
更新于2025-09-19 17:15:36