Electrochromic devices (ECDs) hold great promise for applications in displays and smart military camouflage. However, achieving different electrochromic colored states with compatible integration into a monolithic device remains a significant challenge. In this study, we realized effective color modulation of ECDs by tuning the solvent composition, leveraging the effects of solvent polarity. The resulting ECDs exhibited tunable absorption peaks and color switching behaviors across various solvent systems. The ECDs achieved a high optical contrast of 74%, while maintaining a coloration efficiency of 41.6 cm2 C-1.

Zebrafish serves as a valuable model for studying tissue regeneration due to their comprehensive regenerative abilities, particularly in bone tissue. In this study, a Mueller matrix optical coherence tomography (OCT) system was applied to monitor the regenerative processes of zebrafish caudal fins in vivo. The analysis focused on evaluating the thickness of the caudal fin tip and the distribution of internal bone tissue during the regenerative process. Subsequently, the effect of ectoine solution on the regeneration process was observed and discussed. Our findings revealed that the caudal fin blastema did not exhibit phase-induced polarization characteristics in the Mueller matrix OCT images. Statistical analyses indicated that the caudal fins did not fully regenerate to their original state within 21 days. Furthermore, the results suggested that ectoine solution could enhance tissue regeneration. This approach provides a method for quantifying zebrafish caudal fin regeneration and advances observation techniques for biomedical and clinical applications.

Microlenses or arrays are key elements in many applications.However, their construction methods involve multiple fabrication processes, thereby increasing the complexity and cost of fabrication.In this study, we demonstrate an optically anisotropic, electrically tunable liquid crystal (LC) microlens array using a simple, one-step fabrication method.The microlens array is formed via photopolymerization-induced phase separation inside a polymer/LC composite.It possesses both polarization-dependent and electrically tunable focusing and imaging properties.Without applying voltage, the microlens array has a natural focal length of 8 mm, which is a result of its inherent gradient refractive index profile.Upon applying voltage above the threshold, the LC molecules reorient along the electric field direction and the focal length of the microlens array gradually increases.Based on its superior properties, the microlens array is further used for integral imaging applications, demonstrating electrically tunable central depth plane.Such LC microlens arrays could find numerous potential applications owing to their advantageous features of being flat, ultra-thin, and tunable, including 3D displays, optical interconnects, and more.

Microlenses or arrays are key elements in many applications. However, their construction methods involve multiple fabrication processes, thereby increasing the complexity and cost of fabrication. In this study, we demonstrate an optically anisotropic, electrically tunable liquid crystal (LC) microlens array using a simple, one-step fabrication method. The microlens array is formed via photopolymerization-induced phase separation inside a polymer/LC composite. It possesses both polarization-dependent and electrically tunable focusing and imaging properties. Without applying voltage, the microlens array has a natural focal length of 8 mm, which is a result of its inherent gradient refractive index profile. Upon applying voltage above the threshold, the LC molecules reorient along the electric field direction and the focal length of the microlens array gradually increases. Based on its superior properties, the microlens array is further used for integral imaging applications, demonstrating electrically tunable central depth plane. Such LC microlens arrays could find numerous potential applications owing to their advantageous features of being flat, ultra-thin, and tunable, including 3D displays, optical interconnects, and more.

Chirality induction, transfer, and manipulation have aroused great interest in achiral nanomaterials. Here, we demonstrate strong upconverted circularly polarized luminescence from achiral core-shell upconversion nanoparticles (UCNPs) via a plasmonic chiral metasurface-induced optical chirality transfer. The Yb3+-sensitized core-shell UCNPs with good dispersity exhibit intense upconversion luminescence of Tm3+ and Nd3+ through the energy transfer process. By spin-coating the core-shell UCNPs on this chiral metasurface, strong enhancement and circular polarization modulation of upconversion luminescence can be achieved due to resonant coupling between surface plasmons and upconversion nanoparticles. In the UCNPs-on-metasurface composite, a significant upconversion luminescence enhancement can be achieved with a maximum enhancement factor of 32.63 at 878 nm and an overall enhancement factor of 11.61. The luminescence dissymmetry factor of the induced upconverted circularly polarized luminescence can reach 0.95 at the emission wavelength of 895 nm. The UCNPs-on-metasurface composite yields efficient modulation for the emission intensity and polarization of UCNPs, paving new pathways to many potential applications in imaging, sensing, and anticounterfeiting fields.

Optical metasurfaces are 2D flat elements that consist of spatially arranged meta‐atoms. By carefully designing the metasurface, it is possible to fully control the properties of light in amplitude, phase, and/or polarization. When merged with liquid crystals (LCs), a metasurface can act as a reconfigurable optical component enabling dynamical control of light. However, many reports ignore the influence of the meta‐atom's geometry on the orientation of LCs. Here, it is proposed to synergistically merge LCs and specially designed gold metasurfaces for multiple optical functions. Gold metasurfaces are designed as a template to align the LC molecules in a resolution of ≤2 µm. Meanwhile, the aligned LCs are used to actively control the polarization of the incident light, further achieving active modulation of the plasmonic resonances of gold metasurfaces. The synergistic mergence of LCs and metasurfaces can enable a designed optical device to work simultaneously in both visible and near infrared ranges, which is highly promising for multiple applications simultaneously, such as high‐resolution display, modulation, anti‐counterfeiting, beam deflection, LiDAR, etc.

This work describes a facile thermal transfer printing process for solution-processed high-quality ZnO nanostructures. Nanostructures are synthesized through patterned solution growth and transfer-printed onto a polymer substrate with an inverted configuration. Thus, the shape of the solution-processed ZnO nanostructures can be regulated to have diversified forms, clearly defined edges, and improved surface profiles. To further demonstrate the scalability of such transfer printing process, a metasurface color filter with 300 mu m x 500 mu m "windmill" pattern is designed and more than 300 000 nanorod units included. After the structures are transferred, the color filter can be gradually tuned by O-2 plasma treatment. Moreover, the uneven height of as-synthesized nanorods with different diameters can be evenly rescaled, implying a precise control over the vertical dimension. Lastly, an ultra-high transfer accuracy is validated with a lateral displacement of less than 7 nm. The presented work demonstrates a facile and low-cost transfer printing route toward ZnO-based metasurfaces on flexible substrates.

The dissymmetry factor (|g(lum)|) in circularly polarized luminescence (CPL) shows great significance in many potential applications. The development of upconversion circularly polarized luminescence (UC-CPL) with a large dissymmetry factor is still limited by structural defects, especially in a self-assembly system. Here, a self-organized cholesteric liquid crystals (CLCs) composite is demonstrated, induced by uniaxially aligned upconversion nanorods (UCNRs) film, overcoming the aggregation issue via direct doping. The well-aligned UCNR film serves as a polarized emitter, and the cholesteric superhelixstructure enables the conversion from polarized upconversion luminescence (UCL) to a completely UC-CPL with an ultrahigh |g(lum)| value up to 1.92. Upon changing the concentration of chiral dopants or heating, the chiral UCL can be conveniently modulated via shifting the CLC reflection band to overlap with the UCL band. Moreover, UC-CPL with bidirectional asymmetric polarizations and emissions is achieved via forward and backward excitations. Furthermore, reversible switching from circular to linear polarization of UCL can be achieved by applying an electric field. Such a composite material system features versatile multimode and multiband modulation of UC-CPL with the significantly enhanced dissymmetry factor and multichannel modulation, providing new opportunities for advanced applications in photonics and biological optoelectronics.

Solution-based photochemical reaction is widely utilized in the syntheses of metallic nanocrystals. Although seedless photochemical reaction can avoid pre-treatments, it relies on long, high-energy radiation. Here, this work demonstrates an upconversion-enabled seedless photochemical approach to synthesize grating-like silver nanostructures on a hexagonal NaYF4 microrod via a near-infrared laser excitation. Experimental results show that upconversion emission enables the nucleation and growth of Ag nanoparticles. Meanwhile, the emission can be also precisely tuned and enhanced by in situ growth of silver nanoparticles on the NaYF4 and NaYF4@SiO2 microrods. The maximum enhancement factor of 2 in overall emissions is achieved for the NaYF4@SiO2 microrod. This fabrication approach and results visually confirm the cavity resonance of excitation light inside the microrod via the distribution of Ag nanostructures. Moreover, the in situ grown Ag nanostructures provide a tunable far-field upconversion emission via the plasmonic effect, which is potentially useful for tunable microlasers, biosensing, antibacterial, and catalytic applications.

Chiral metasurfaces can exhibit a strong circular dichroism, but it is limited by the complicated fabrication procedure and alignment errors. Here, a new type of self-aligned suspended chiral bilayer metasurface with only one-step electron beam lithography exposure is demonstrated. A significant optical chirality of 221° µm-1 can be realized using suspended metasurfaces with a thickness of 100 nm. Furthermore, this study experimentally demonstrates that such a structure is capable of label-free discrimination of the chiral molecules at zeptomole level, exhibiting a much higher sensitivity (orders of magnitude) compared to the conventional circular dichroism spectroscopy. The fundamental principles for chiral sensing using molecules-metasurfaces interactions are explored. Benefiting from the giant chiroptical response, the proposed metadevice may offer promising applications for ultrathin circular polarizers, chiral molecular detectors, and asymmetry information processing.

Actively tunable or reconfigurable structural colors are highly promising in future development for high resolution imaging and displaying applications. To this end, we demonstrate switchable structural colors covering the entire visible range by integrating aluminum nanoaperture arrays with nematic liquid crystals. The geometrically anisotropic design of the nanoapertures provides strong polarization-dependent coloration. By overlaying a nematic liquid crystal layer, we further demonstrate switchable ability of the structural colors by either changing the polarization of the incident light or applying an external voltage. The switchable structural colors have a fast response time of 28 ms at a driving voltage of 6.5 V. Furthermore, colorful patterns are demonstrated by coding the colors with various dimensions of nanoaperture arrays with dual switching modes. Our proposed technique in this work provides a dual-mode switchable structural colors, which is highly promising for polarimetric displays, imaging sensors, and visual cryptography.

In recent years, metasurfaces have received considerable attention owing to their versatile range of applications. However, in the case of metal‐oxide‐based dielectric metasurfaces, the difficulty and cost of a conventional top‐down nano‐fabrication process largely hinder their applications. In this work, a fabrication method is proposed for dielectric metasurfaces based on the solution‐phase epitaxy of ZnO nanorods. Using this method, precise control of the size and position of the synthesized ZnO nanostructures is achieved. Furthermore, a functional subtractive color filter is also designed and fabricated using this approach. The diameters of the synthesized ZnO nanorods range from 180 to 320 nm, and the subtractive color filter exhibits a wide color tuning ability from yellow to magenta to cyan. Such solution‐based bottom‐up fabrication of ZnO nanorods eliminates the need for dry etching, and demonstrates the potential to grow high‐aspect‐ratio ZnO nanostructures for efficient dielectric metasurfaces.

SID Symposium Digest of Technical PapersVolume 52, Issue S2 p. 570-570 Technical Sessions: Session 47: Beyond Display (LCT) 47.1: Invited Paper: Merging Liquid Crystals and Metasurfaces for Optical Multifunctions Jiawei Wang, Jiawei Wang Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorKe Li, Ke Li Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorHuilin He, Huilin He Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorWengfeng Cai, Wengfeng Cai Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorJianxun Liu, Jianxun Liu Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorYan Jun Liu, Corresponding Author Yan Jun Liu yjliu@sustech.edu.cn Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this author Jiawei Wang, Jiawei Wang Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorKe Li, Ke Li Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorHuilin He, Huilin He Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorWengfeng Cai, Wengfeng Cai Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorJianxun Liu, Jianxun Liu Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this authorYan Jun Liu, Corresponding Author Yan Jun Liu yjliu@sustech.edu.cn Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055 ChinaSearch for more papers by this author First published: 26 August 2021 https://doi.org/10.1002/sdtp.15203AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume52, IssueS2International Conference on Display Technology (ICDT 2021)August 2021Pages 570-570 RelatedInformation

Metasurface-based structural coloration is a promising enabling technology for advanced optical encryption with a high-security level. Herein, we propose a paradigm of electrically switchable, polarization-sensitive optical encryption based on designed metasurfaces integrated with polymer-dispersed liquid crystals. The metasurfaces consist of anisotropic and isotropic aluminum nanoaperture arrays. Optical images can be encrypted by elaborately arranging anisotropic and isotropic nanoapertures based on their polarization-dependent plasmonic resonance characteristics. We demonstrate high-quality encrypted images and QR codes with electrically switchable, polarization-sensitive properties based on PDLC-integrated aluminum nanoaperture arrays. The proposed technique can be applied to many fields including high-security optical encryption, security tags, anticounterfeiting, multichannel imaging, and dynamic displays.

本文以"聚合物分散液晶光电器件设计与制备"实验为例阐述了将经典光学实验与前沿内容结合在教学中的运用.通过本文的实验设计可使学生了解聚合物分散液晶材料,掌握基于激光曝光技术制备包括智能窗、全息光栅、叉形光栅的方法和过程,重点引入涡旋光这一前沿光学研究课题,掌握利用叉形光栅产生涡旋光的原理与过程,并学习利用光学基础中的马赫曾德尔干涉仪检测涡旋光拓扑核的方法.通过实验,使学生意识到科学前沿并非空中楼阁,而是与基础理论密切相关.进而激发学生学习探索的热情,加强其基础知识储备,培养其创新型思维,为将来进一步的科研及工作打好基础.

Lanthanide-doped particles exhibit unique polarization-dependent luminescence due to the anisotropic crystalline local symmetry surrounding the emitter. Precise control of the orientation of particles shows great significance for exploiting the luminescent polarization and their potential applications. Here, we demonstrated a facile polypropylene-aided shear-driven method to obtain large-scale orientationally ordered upconversion nanorods, showing a liquid-crystalline nematic phase. Upconversion nanorods with low aspect ratios were well-aligned with the crystalline c-axis along the shearing direction using monodispersed colloid nanorods as the nanoink. The order parameter of aligned upconversion nanorods can reach up to 0.95. The nematic upconversion nanorods demonstrated strong polarization-dependent luminescence with the high degrees of polarization of the 4F9/2 sublevels at 657 and 661 nm being 0.47 and 0.59, respectively. Taking advantage of these mesoscopic well-aligned upconversion nanorods, their peculiar polarized emissions are potentially useful for some interdisciplinary applications such as polarization-sensitive bioprobes and anticounterfeiting.

We report holographic fabrication of nanoporous distributed Bragg reflector (DBR) films with periodic nanoscale porosity via a single-prism conuration. The nanoporous DBR films result from the phase separation in a material recipe, which consists of a polymerizable acrylate monomer and nonreactive volatile solvent. By changing the interfering angle of two laser beams, we achieve the nanoporous DBR films with highly reflective red, green, and blue colors. The reflection band of the nanoporous DBR films can be tuned by further filling different liquids into the pores inside the films, resulting in the color change accordingly. Experimental results show that such kinds of nanoporous DBR films could be potentially useful for many applications, such as color filters and refractive index sensors.

Homeotropic alignment of liquid crystals (LCs) is one of the key modes used in commercial liquid crystal displays (LCDs) due to its advantages, such as high contrast ratios and fast response speed. Here, we report stable homeotropic LC alignment with a small pretilt angle in a nematic, negative LC host doped with additives including self-aligning agents, photoresponsive azo dyes, and reactive mesogen via an in situ self-assembled, dual-wavelength photoalignment approach. The underlying mechanism of stable, pretilted homeotropic LC alignment was further analyzed in detail. The achieved pretilted homeotropic LC cells are very stable against heat and UV light exposure and demonstrate excellent electro-optical characteristics. The experimental results show that such a noncontact, simple homeotropic alignment technique has big potential in many applications, such as high-quality LCDs, spatial light modulators, and other optoelectronic devices.

Electrically switchable photonic crystals are demonstrated based on TiO2 inverse opals infiltrated with liquid crystals. Macroporous anatase TiO2 inverse opals are fabricated from polystyrene opal templates through a sandwich vacuum backfilled method and followed by calcination. Upon liquid crystal infiltration, the optical properties of the hybrid organic/inorganic structure are characterized by reflectance measurements of the Bragg peak, the position of which can be switched using an external electric field. The physical mechanism underlying this switchable behavior is the reorientation of the liquid crystal molecules inside the spherical voids by the applied electric field, resulting in a significant change of the refractive index contrast between the liquid crystal and the TiO2 inverse opal. With advantageous features of cost-effective fabrication, easy integration, and electric control, such TiO2 inverse opals infiltrated with liquid crystals could play an important role in future development of active photonic devices.