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Terahertz (THz) metasurfaces have emerged as a powerful tool for manipulating THz wavefronts, typically achieved by adjusting various geometric parameters. In this study, an approach is introduced by incorporating interlayer coupling into twisted stacking metasurface design to completely control the amplitude and phase of circularly polarized THz waves. By leveraging the interlayer coupling effect and the Pancharatnam–Berry phase, the study achieves efficient control over transmission phase and amplitude by simply adjusting the relative twist angle between paired C‐shaped split‐ring resonators. To validate the concept, a holographic metasurface is fabricated and characterized, providing experimental evidence of its THz wavefront manipulation capabilities. This design strategy presents a versatile and tunable solution for THz wave control, promising applications in a wide range of functional devices. [ABSTRACT FROM AUTHOR]

Sodium metal battery is considered as one of the most promising energy storage/conversion devices due to their high energy density, and abundant sodium reserves. However, its development is hampered by the limited metallic utilization and detrimental sodium dendrite growth ascribed to the unstable, and fragile solid electrolyte interphase (SEI). Here, the high stable and modulus SEI is constructed with a component of a thin and dense layer of high Na‐ion conductive Na2SiO3. It is in situ formed by the reaction between sodium anode and fish‐skin structure separator, which exhibits a 3D porous polyvinylidene fluoride‐based framework embedded with thin and robust vermiculite sheets. The robust interphase cannot only suppress sodium dendrite growth but also enable high energy density with small interphase‐consumed Na ions in anode‐less batteries. Accordingly, the as‐assembled NaNi1/3Fe1/3Mn1/3O2//Na cell shows 83% capacity retention after 5000 cycles at a rate of 5 °C. Moreover, the proof‐of‐concept pouch cells deliver an energy density of 205 Wh kg−1 (based on the total mass of the battery), and high safety (not catching fire after punctured) under anode‐less condition (with a low negative/positive capacity ratio of ≈2.1). [ABSTRACT FROM AUTHOR]

Seeking new ways to actively control the phase using metasurfaces has gained significant attention in recent years, which is the key to achieve controllable wavefronts under external stimuli. Among various active phase control mechanisms, a mechanical method based on gap tuning, termed as gap‐tuned metasurface here, has shown promise in continuous phase adjustment. However, previous studies face limitations in independent and complete phase control at different gap distances, which is crucial in dual‐function switching applications. In this study, a novel type of gap‐tuned metasurfaces are proposed, which can overcome the above limitations through simultaneously manipulating the Pancharatnam–Berry phase and gap‐induced dynamic phase under circularly polarized incidences. Two exemplary gap‐tuned metasurfaces capable of orbital angular momentum (OAM) switching and focusing‐polarity switching are experimentally demonstrated. Furthermore, the special dynamic phase design also exhibits phase conjugate property similar to the Pancharatnam–Berry phase, making circular polarization handedness an alternative route for dual‐function switching. This method provides a straightforward and effective means for the development of active wavefront control devices. [ABSTRACT FROM AUTHOR]

Metasurfaces have garnered significant interest owing to their inherent advantages over traditional optical components in manipulating electromagnetic waves unconventionally. Among the fundamental building blocks of metasurfaces, C‐shaped‐split‐ring resonators (CSRRs) have emerged as a highly promising option, enabling strong resonances and precise control over various characteristics of electromagnetic waves, such as phase, amplitude, and polarization. This review aims to showcase recent advancements in CSRR metasurfaces for manipulating THz waves, particularly focusing on both passive and active methods employed for controlling THz waves using single‐layer and multi‐layer CSRR metasurfaces. Moreover, this review will provide valuable insights into potential research directions in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

Recently, it has become imperative to develop high energy density as well as high safety lithium‐ion batteries (LIBS) to meet the growing energy demand. Among the anode materials used in LIBs, the currently used commercial graphite has low capacity and is a safety hazard due to the formation of lithium dendrites during the reaction. Among the transition metal oxide (TMO) anode materials, TMO based on the intercalation reaction mechanism has a more stable structure and is less prone to volume expansion than TMO based on the conversion reaction mechanism, especially the niobium‐based oxide in it has attracted much attention. Niobium‐based oxides have a high operating potential to inhibit the formation of lithium dendrites and lithium deposits to ensure safety, and have stable and fast lithium ion transport channels with excellent multiplicative performance. This review summarizes the recent developments of niobium‐based oxides as anode materials for lithium‐ion batteries, discusses the special structure and electrochemical reaction mechanism of the materials, the synthesis methods and morphology of nanostructures, deficiencies and improvement strategies, and looks into the future developments and challenges of niobium‐based oxide anode materials. [ABSTRACT FROM AUTHOR]

The cycling and rate capabilities of LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode material under high cut‐off voltage (≥4.5 V) and high current density have attracted much attention. However, the material's insufficient intrinsic electronic/ion conductivity and interface instability are still key issues restricting its electrochemical performance.In this paper, a graphene/Ta2O5 co‐coating layer is successfully fabricated on the surface of NCM523 to form a cathode material of GTa‐NCM523 to enhance both the electron and lithium‐ion transport during cathode operation. The GTa‐NCM523 cathode material achieves a discharge specific capacity of 147.4 mAh g−1 after 600 cycles at a voltage of 3.0–4.5 V and a rate of 1 C (180 mA g−1) with a capacity retention rate of 81.4 %. In contrast, the uncoated NCM523 only retains 63.2 % of its capability. At an elevated rate of 10 C (1800 mA g−1), the GTa‐NCM523 can achieve a discharge‐specific capacity of up to 113.5 mAh g−1, which is 43.7 % higher than the uncoated NCM523. The co‐coating layer can inhibit HF erosion and accelerate the movement of lithium‐ions and electrons, which account for the superior electrochemical characteristics of the co‐coating layer comprised of graphene and Ta2O5. [ABSTRACT FROM AUTHOR]

Terahertz (THz) metasurfaces have emerged as powerful tools to modulate the wavefronts of THz radiation fully. Smart designs and fabrication are essential for enhancing the flexibility and encryption security of THz metasurfaces. In addition to digital coding metasurfaces and microelectromechanical systems, one method to realize dynamic THz metasurfaces is to utilize an active material. In this paper, a dynamic THz metasurface, which is combined with the phase‐change material VO2 and can be thermally controlled to achieve optical encryption, is proposed. Based on the electromagnetically induced transparency effect and by arranging the antennas in advance according to a specific hologram, a secret image can be encoded into the metasurface. At room temperature, the transmitted light field is an irregular light spot with no useful information. If the temperature increases above the phase‐change temperature, the encrypted hologram can be reconstructed. Moreover, owing to the distinct characteristics of VO2, the phase‐change temperature required during decryption is not very high, and the entire process is reversible. It is expected that, in combination with updated processing technology, such metasurfaces can be practically applied to the next generation of optical encryption or optical anticounterfeiting in the future. [ABSTRACT FROM AUTHOR]

V3O7·H2O (VO) is an attractive cathode material for high‐capacity aqueous Zn‐ion batteries (AZIBs), but it is limited by slow ion mobility and low working platform voltage. Here, a 1,3‐propane diamine (DP)‐intercalated VO with nanoribbon‐assembled thorn flower‐like structure is fabricated by a facile hydrothermal method, noted as VO‐DP. The study shows that the zinc ion diffusion coefficient in VO‐DP (3.1 × 10−8 cm−2 s−1) is five orders of magnitude higher than that of a pure VO counterpart. Auxiliary density functional theory simulation shows that the embedded energy of zinc ions in VO‐DP significantly decreases from 0.24 to −2.5 eV, thus leading to excellent diffusion kinetics and superior rate performance. Benefiting from these unique properties, AZIBs composed of VO‐DP cathodes exhibit high operating voltage (0.89 V), remarkable capacities of 473 mA h g−1 at 0.05 A g−1, excellent rate capability (144 mA h g−1 at 10 A g−1) and long‐term cycling performance (73% capacity retention over 15 000 cycles at 10 A g−1). [ABSTRACT FROM AUTHOR]

Generation and manipulation of terahertz (THz) waves are of vital importance for advancing THz technology. Nonlinear metasurfaces allow effective integration of both processes into a single compact device. However, such existing THz devices commonly rely on utilizing a single meta‐atom, which has fixed THz generation properties and thus limits the range of achievable functionalities. Here, it is demonstrate how coupling between different meta‐atoms within the unit‐cell can be used as a degree of freedom for controlling nonlinear THz generation, where achiral coupling provides full control over the amplitude of the generated THz field, while chiral coupling makes the THz generation sensitive to the handedness of the pump polarization. In particular, chiral coupling allows the realization of multiplexed pump‐handedness‐selective nonlinear metasurfaces, which is illustrated experimentally by selectively generating THz beams with different orbital angular momentum with a single nonlinear metasurface. This approach provides opportunities for developing various integrated nonlinear THz devices. [ABSTRACT FROM AUTHOR]

Geometric phase metasurfaces, as one of the main branches of meta‐optics, have attracted enormous interest in the last two decades. Recently, through rotating a set of subwavelength dipole sources, geometric phase concept has been extended to near‐field regime for the control of surface plasmons (SPs). Despite this progress, puzzles and shortcomings still exist: it is curious that geometric phases equal to once and twice the rotation angle of dipole source are both reported for SP controls, and the control strategies examined thus far only work for a single wavelength. Hereby, a rigorous derivation of the SP excitation of dipole sources upon circularly polarized illumination is performed, and the rotation dependence and in‐plane coordinate correlation of geometric phase control of SPs is clarified. Moreover, a holographic approach is proposed to implement multiplexed geometric phase control, experimentally demonstrating several metalenses that can couple and steer the incident circular polarizations of four wavelengths and two spin directions to different SP focusing beams. This work will pave an avenue toward the development of integrated and multiplexed SP devices. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable sodium‐ion batteries have attracted increasing attention for large‐scale energy storage applications due to their intrinsic safety and sufficient sodium reserves. The tunnel‐type Na0.44MnO2 has been widely investigated as a promising cathode because of its low cost and high theoretical capacity (120 mAh g−1). However, a capacity higher than 45 mAh g−1 for Na0.44MnO2 in aqueous electrolyte is difficult to obtain. Here, it is found that there is a competitive insertion reaction between H+ and Na+, and the diffusion energy barriers of Na+ are increased along with high Na content in Na0.44MnO2, but the opposite is true for protons. By decreasing the diffusion energy barrier of Na+ and increasing the diffusion energy barrier of protons, a high reversible capacity of 101 mAh g−1 for Na0.44MnO2 in aqueous electrolytes is achieved for the first time. Coupled with a quinone anode, the full cell delivers a high energy density of 60 Wh kg−1 and retains 85% of its capacity for 1200 cycles at a 1 C rate. [ABSTRACT FROM AUTHOR]

Terahertz (THz) vortex beams with helical wavefronts promise many important applications ranging from high‐speed wireless communications to super‐resolution imaging. Conventional methods to generate THz beams mostly rely on manipulating and converting the incident THz beams. Herein is proposed and experimentally demonstrated how the patterned indium tin oxide (ITO) film, i.e., ITO Fresnel zone plate (ITO‐FZP), enables direct emission of focused THz vortex beams with desired orbital angular momentums. Such THz vortex‐beam emitters are based on the straightforward nonlinear THz emission through the patterned ITO film under femtosecond laser excitation. The proposed approach greatly integrates THz emission and vortex‐beam generation processes, which is low cost, robust, and easy to fabricate. [ABSTRACT FROM AUTHOR]

Light is a complex vectorial field characterized by its amplitude, phase, and polarization properties, which can be further represented by four basic parameters, that is, amplitudes and phases of two orthogonally polarized components. Controlling these parameters simultaneously and independently at will using metasurfaces are essential in arbitrarily manipulating the light propagation. However, most of the studies so far commonly require a great number of different meta‐atoms or rely on diffraction under oblique incidence, which lack convenience and flexibility in design and implementation. Here, a new metasurface paradigm is proposed that can completely manipulate the amplitudes and phases of two spin components based on the interference effect, where only two different meta‐atoms are applied. For proof‐of‐concept demonstration, two five‐channel meta‐holograms for imaging and information encryption are designed and experimentally characterized. The interference method provides a simple route toward compact complex and multifunctional meta‐devices. [ABSTRACT FROM AUTHOR]

Metasurfaces are a class of planar optical components that are engineered to manipulate electromagnetic waves, including their spin states in terms of circular polarizations. For example, the Pancharatnam–Berry (PB) phase has been exploited in metasurfaces for various spin functionalities, but these spin functionalities, exhibit conjugate relations for spin states. Recent advances combining the PB phase and propagation phase have implemented completely independent spin functionalities for spin states. However, the spin functionalities are fixed once the metasurfaces are designed. Here, this work proposes and demonstrates that the spin functionalities designed from the PB phase and propagation phase can be further extended by simply rotating the elements in a metasurface. This extension is based on a relationship between phase profiles of spin states that are acquired before and after the rotation. Proof‐of‐concept demonstrations are performed for the extended spin functionalities, including the conversion from spin angular momentum to orbital angular momentum, and spin‐dependent holograms. This extension may find use in relevant applications such as polarized display and dual‐polarized holography. [ABSTRACT FROM AUTHOR]

Efficient and flexible manipulation of terahertz (THz) polarization in a broadband manner using metasurfaces has attracted continuous attention in recent years. Previous studies have commonly applied multilayer metallic resonators or bonded dielectric structures as the basic units, which are affected by the spacer loss or bonding difficulty and stability. Here, a new design scheme is proposed based on an all‐metal stereo U‐shaped meta‐atom working in a reflection configuration. The stereo metasurface functions as an efficient and broadband THz waveplate with tailorable birefringence simply controlled by the sunken depth. Such an intriguing property is experimentally verified by a reflection‐type THz half‐waveplate. The polarization conversion ratio is higher than 90%, with 69% relative bandwidth and over 85° angle tolerance for incidence. Furthermore, an efficient and broadband meta‐grating based on the Pancharatnam–Berry phase method is also experimentally demonstrated. The proposed strategy enriches the design degrees of freedom of polarization‐related metasurfaces and may find broad applications in realizing various functional devices. [ABSTRACT FROM AUTHOR]

Since the late 19th century, enormous endeavors have been made in extending the scope and capability of optical interferometers. Recently, plasmonic vortices that strongly confine the orbital angular momentum to surface have attracted considerable attention. However, current research interests in this area have focused on the mechanisms and dynamics of polarization‐dependent single plasmonic vortex generation and evolution, while the interference between different plasmonic vortices for practical applications has been unexplored. Here, a method for flexible on‐chip spin‐to‐orbital angular momentum conversion is introduced, resulting in exotic interferograms. Based on this method, a new form of interferometers that is realized by the interference between customized plasmonic vortices is demonstrated. Within wavelength‐scale dimension, the proposed plasmonic vortex interferometers exhibit superior performance to directly measure the polarization state, spin and orbital angular momentum of incident beams. The proposed interferometry is straightforward and robust, and can be expected to be applied to different scenarios, fueling fundamental advances and applications alike. [ABSTRACT FROM AUTHOR]

Coupling free‐space light into surface plasmons (SPs) has traditionally faced challenges in arbitrarily controlling the directionality of the SPs with respect to the incident polarization. Recently reported polarization‐dependent directional coupling of SPs using metasurfaces has attracted enormous attention for its promise in developing innovative and on‐demand plasmonic devices. However, further progress has been hampered by the limitation in designating the directional coupling with tailorable polarization‐dependent feature and compatible ability to incidence of complex polarization distribution. Here, a directional coupling strategy is introduced to overcome these limits. It is demonstrated that, by utilizing the interference between two pairs of slit resonators with different resonance responses, the directional SP coupling can be expanded to arbitrary group of polarized incidence by simply varying their relative distance, and the SP coupling direction will reverse under the corresponding orthogonally polarized incidence without affecting the efficiency. To exhibit the versatile design capability of the strategy, it is further utilized to construct several polarization‐dependent plasmonic devices for controlling SP propagations, including two SP metalenses and a plasmonic Airy beam launcher, in which it is shown that the device can even be designed to work for non‐uniformly polarized incidence. The strategy paves a reliable route towards many practical on‐chip applications. [ABSTRACT FROM AUTHOR]

The aqueous rechargeable sodium‐ion battery (ARSIB) is considered to be the most promising candidate for large‐scale energy storage applications, due to its low cost, safety, and eco‐friendliness. However, the poor cycle life and low energy density of ARSIB impede its practical applications. In this context, hollow NaTi2(PO4)3 nanocubes anode is engineered through a facile, low‐cost, and large‐scale hydrothermal approach. Na0.44MnO2 cathode delivers a high capacity of 75.16 mAh g−1 with the compensation of sodium ions by the zinc metal‐induced pre‐sodiation of the anode in a deep eutectic electrolyte. The well‐designed structure in hollow carbon‐coated NaTi2(PO4)3 nanocubes enables high stability and rate performance. Moreover, the adoption of deep eutectic electrolytes can minimize the Mn dissolution in the Na0.44MnO2 cathode. When coupling the cathode and anode, the as‐assembled ARSIB with a deep eutectic electrolyte exhibits an ultralong cycle life up to 3500 cycles (with capacity retention of 90%), an ultrahigh energy density of 50.0 Wh kg−1, and superior rate capability (maximum power density of 1500 W kg−1). This ARSIB represents an alternative promising candidate for large‐scale electrochemical energy storage. [ABSTRACT FROM AUTHOR]

The achievable functionalities of metasurfaces are mainly determined by the capability of their unit cells to control the local electromagnetic responses. To realize full control over light, it is highly desired to find a kind of unit cell that can achieve complete control of the phase, amplitude, and polarization, which remains a big challenge and cannot be fully replaced with iteration algorithms. Here, such control is achieved by exploiting interference in a dielectric unit cell composed of multiple meta‐atoms, namely, a meta‐molecule. This strategy provides sufficient effective geometric degrees of freedom within the meta‐molecule to enable full control over its optical properties, as is demonstrated here with a complete meta‐molecule database. As a proof‐of‐concept demonstration, polarization‐independent, polarization‐dependent, and vectorial meta‐holograms are proposed and experimentally characterized. High imaging quality is achieved in both the measured intensity and phase distributions. This is allowed by the ability of the meta‐molecules to fully record the information of the target images. This strategy opens a direct way toward optical devices with various desirable functionalities. [ABSTRACT FROM AUTHOR]

Extreme terahertz (THz) science and technologies, the next disruptive frontier in nonlinear optics, provide multifaceted capabilities for exploring strong light‐matter interactions in a variety of physical systems. However, current techniques involve the need for an extremely high‐field free space THz source that is difficult to generate and has limited investigations to a rather weak and linear regime of light‐matter interactions. Therefore, new approaches are being sought for the tight confinement of THz waves that can induce nonlinear effects. Here, a nonlinear "tera‐nano" metasurface is demonstrated exhibiting extremely large THz nonlinearity and sensitive self‐modulation of resonances at moderate incident THz field strengths. A record deep‐subwavelength (≈λ/33 000) confinement of strongly enhanced (≈3200) THz field in a nano‐gap (15 nm) exhibits remarkable THz field‐tailored nonlinearity. Further, ultrafast injection of photocarriers reveals a competition between nonlinear THz field‐induced intervalley scattering and optically driven interband excitations. The results on "tera‐nano" metasurfaces enable a novel platform to realize enhanced nonlinear nano/micro composites for field‐sensitive extreme THz nonlinear applications without the need for intense THz light sources. [ABSTRACT FROM AUTHOR]

Chiral media exhibit optical activity, which manifests itself as differential retardation and attenuation of circularly polarized electromagnetic waves of opposite handedness. This effect can be described by different refractive indices for left‐ and right‐handed waves and yields a negative index in extreme cases. Here, active control of chirality, optical activity, and refractive index is demonstrated. These phenomena are observed in a terahertz metamaterial based on 3D‐chiral metallic resonators and achiral vanadium dioxide inclusions. The chiral structure exhibits pronounced optical activity and a negative refractive index at room temperature when vanadium dioxide is in its insulating phase. Upon heating, the insulator‐to‐metal phase transition of vanadium dioxide effectively renders the structure achiral, resulting in absence of optical activity and a positive refractive index. The origin of the structure's chiral response is traced to magnetic coupling between front and back of the structure, whereas the temperature‐controlled chiral‐to‐achiral transition is found to correspond to a transition from magnetic to electric dipole excitations. The use of a fourfold rotationally symmetric design avoids linear birefringence and dichroism, allowing such a structure to operate as tunable polarization rotator, adjustable linear polarization converter, and switchable circular polarizer. [ABSTRACT FROM AUTHOR]

Recently, chiral metasurfaces have drawn enormous attentions due to their flexibility in realizing nearly arbitrary chiral effect with designable strength. One intriguing direction in this field is chiral‐selective absorption. However, previous studies mostly require multilayer design and meanwhile often work in a passive way. Here, for the first time to the authors' knowledge, a chiral‐selective metasurface absorber is experimentally demonstrated with a single‐layer free‐standing metasurface using coherent control method, where the strength of the chiral‐selective behavior can be actively tuned with a 100% modulation depth by simply changing the phase difference between the two coherent inputs. Specifically, under coherent symmetric illumination, near unity absorption is achieved for one circularly polarized incidence, while high‐efficiency cross‐polarization conversion is obtained for the other circularly polarized incidence. Such chiral‐selective absorption property is quite suitable for achieving coherent chiral‐selective wavefront control for the unabsorbed circularly polarized incidence. Three coherent chiral metagratings are designed and experimentally characterized by further employing Pancharatnam–Berry phase method and multiplexed method, where very good performances are achieved. The proposed approach on coherent control can enrich the functionalities and also improve the performances of the conventional single‐layer metasurfaces, which can find extending applications in various practical cases. [ABSTRACT FROM AUTHOR]

Spoof surface plasmons (SSPs) play crucial roles in terahertz (THz) near‐field photonics. However, both high‐efficiency excitation and wavefront engineering of SSPs remain great challenges, which hinder their wide applications in practice. Here, a scheme is proposed to simultaneously achieve these two goals efficiently using a single ultracompact device. First, it is shown that a gradient meta‐coupler constructed by high‐efficiency Pancharatnam–Berry (PB) meta‐atoms can convert circularly polarized (CP) THz beams into SSPs with absolute efficiency up to 60%. Encoding a parabolic phase profile into the meta‐coupler based on the PB mechanism, it is demonstrated that the device can covert CP beams into SSPs with focusing or defocusing wavefronts, dictated by the chirality of the incident wave. Finally, two distinct chirality‐dependent phase distributions are encoded into the meta‐coupler design by combining the PB and resonance phase mechanisms, and it is demonstrated that the resulting meta‐device can achieve SSP excitations with chirality‐delinked bifunctional wavefront engineering. THz near‐field experiments are performed to characterize all three devices, in excellent agreement with full‐wave simulations. The results pave the road to realize ultracompact devices integrating different functionalities on near‐field manipulations, which can find many applications (e.g., optical sensing, imaging, on‐chip photonics, etc.) in different frequency domains. [ABSTRACT FROM AUTHOR]

Mirrors are widely used for redirection of electromagnetic waves in optical systems, making them arguably the most irreplaceable optical component. Metamaterial‐based chiral mirrors, composed of a 2D‐chiral planar metallic structure backed by a conventional mirror, reflect one circular polarization without changing its handedness, while absorbing the other. Here, three types of switchable chiral mirror are demonstrated. Switching from a chiral mirror to either a conventional mirror, a handedness‐preserving mirror, or a chiral mirror of opposite handedness, is realized. These advances are underpinned by switching the handedness of 2D‐chiral metamaterial and the associated effect of circular conversion dichroism, which is reported here for the first time. Switching is achieved by exploiting the temperature‐activated dielectric‐to‐metal phase transition of vanadium dioxide to modify the symmetry and chirality of the metamaterial's resonators. Current distributions explain the temperature‐controlled optical properties by handedness‐selective excitation of reflective electric dipole and absorbing magnetic dipole modes. [ABSTRACT FROM AUTHOR]

Biphilic surfaces having spatially distinct wetting have the potential to enable a plethora of applications ranging from fog harvesting, microfluidics, advanced manufacturing, and pumpless fluid transfer. However, complex and costly fabrication along with poor durability have hindered the widespread utilization of biphilic surfaces. Here, hierarchical biphilic micro/nanostructured surfaces passively functionalized by the atmosphere are demonstrated as a platform to create scalable and abrasion‐resistant biphilic interfaces. Biphilic hierarchical copper oxide (CuO) nanowires are fabricated on copper substrates via laser ablation followed by thermal oxidation. The surfaces spontaneously become globally superhydrophobic and locally hydrophilic due to the adsorption of airborne volatile organic compounds on the ultrahigh surface energy CuO nanowires. The curvature‐dependent spatial variation in nanowire morphology enables local roughness variation and wetting contrast without the need for selective functionalization. Coalescence‐induced droplet jumping and water vapor condensation experiments demonstrate global superhydrophobicity with discrete local hydrophilicity. In addition to enhanced fog harvesting rates, the surfaces are demonstrated to have repeatable self‐healing function with enhanced abrasion resistance compared to single‐tier structured surfaces. The work not only develops a facile method of fabricating scalable biphilic surfaces via nanoscale structure variation and atmosphere‐mediated surface modification, but also provides insights into the role of wetting contrast on droplet dynamics. [ABSTRACT FROM AUTHOR]

Aqueous lithium/sodium‐ion batteries (AIBs) have received increasing attention because of their intrinsic safety. However, the narrow electrochemical stability window (1.23 V) of the aqueous electrolyte significantly hinders the development of AIBs, especially the choice of electrode materials. Here, an aqueous electrolyte composed of LiClO4, urea, and H2O, which allows the electrochemical stability window to be expanded to 3.0 V, is developed. Novel [Li (H2O)x(organic)y]+ primary solvation sheath structures are developed in this aqueous electrolyte, which contribute to the formation of solid–electrolyte interface layers on the surfaces of both the cathode and anode. The expanded electrochemical stability window enables the construction of full aqueous Li‐ion batteries with LiMn2O4 cathodes and Mo6S8 anodes, demonstrating an operating voltage of 2.1 V and stability over 2000 cycles. Furthermore, a symmetric aqueous Na‐ion battery using Na3V2(PO4)3 as both the cathode and anode exhibits operating voltage of 1.7 V and stability over 1000 cycles at a rate of 5 C. [ABSTRACT FROM AUTHOR]

Abstract: Chiral responses are optical responses involving circular polarizations. Controlling the chiral response in a flexible way is very important in optical manipulations. Chiral metamaterials have thus drawn enormous interest due to their flexible designing feature. However, most of the previous studies are mainly realized by designing the structure of the individual meta‐atom. Meanwhile, to enhance the response, complex design and fabrication processes are typically required. Here, by introducing spin‐dependent propagating surface plasmons and spin‐selective interference, giant spin‐resolved transmission is achieved in a simple meta‐hole structure. In this interaction process, spin‐orbital angular momentum conversion plays an essential role. By controlling the phase difference between the interference components, controllable spin‐resolved transmission is achieved. Furthermore, such method can also be applied to realize spin‐resolved excitation of surface plasmons. The proposed controlling strategy offers a versatile platform for a variety of promising applications, such as polarization control, asymmetric transmission, surface plasmon excitation, and on‐chip chiral manipulation. [ABSTRACT FROM AUTHOR]

Abstract: Surface plasmons (SPs) promise versatile potential applications in many aspects and thus have been a subject of enormous interest. As the most essential functionality, efficient coupling of free‐space light into complex SP field is of particular interest in current research. Most existing methods only focus on either efficient coupling or complex SP field generation, which is insufficient to support the ever‐increasing demand of practical applications. Herein, it is demonstrated both theoretically and experimentally that a metasurface composed of properly designed C‐shaped slit resonators can function as an efficient SP coupler. More importantly, it is shown that the phase and amplitude of the coupled SPs can be simultaneously manipulated, which would offer considerable design flexibilities for complex SP launching. This methodology can provide a wide platform for the design and fabrication of high‐performance plasmonic devices in the future, especially large‐area ones in practical applications. [ABSTRACT FROM AUTHOR]

One type of biocompatible nanoparticles functionalized with folate and 99mTc was successfully synthesized. Maleimide‐folic acid (Mal‐FA) was selected to covalently conjugate with ‐SH of the nanoparticles (NPs) to prepare NPs‐FA for targeting. 99mTc was selected to conjugate with ‐NH2 and ‐SH groups of cysteine residues on the surface of NPs to prepare NPs‐FA‐99mTc for radioactive counting. The ability to target folate receptors of NPs‐FA‐99mTc was assessed in uptake studies with folate‐receptor–positive human HepG2 cells. The results showed that the as‐prepared NPs can selectively uptake by folate receptor‐overexpressing HepG2 tumor cells in vitro. The oligomeric hybrid NPs radiolabeled with 99mTc may develop to be SPECT/CT imaging biomaterials with high selectivity. [ABSTRACT FROM AUTHOR]

Metasurfaces, 2D artificial electromagnetic media, open up a new frontier of functional device design ranging from radio waves to the visible region. Particularly, metasurface-based lenses are indispensable in various practical terahertz applications. The authors aim at achieving flexible and robust metalenses for efficient terahertz wave control. In general, resolution and efficiency are two inevitable parameters in determining the focusing and imaging abilities of lenses, which however are rarely experimentally demonstrated in the terahertz band. In this Communication, three broadband and robust metalenses with nonlinear phase profiles are proposed, all of which are experimentally investigated by using near-field scanning terahertz microscopy (NSTM) with a spatial resolution of 50 µm. The measurement shows that the metalens can focus a 0.95 THz wave to a spot size of 580 µm and achieve a transmittance efficiency of 45%. In addition, the NSTM system facilitates an experimental investigation of the incidence angle dependence of the terahertz metalens, which proves the robust focusing feature of the proposed device. This demonstration delivers a promising metasurface design for potential applications in imaging and information processing that may be of interest for the entire electromagnetic spectrum. [ABSTRACT FROM AUTHOR]

ABSTRACT Flexible freestanding cotton-graphene (CGN) composites were prepared by a simple immersion and freeze-drying method and a thermal annealing process together. The composites had a constant cotton microstructure covered by graphene. The microstructure and morphology of the composites could be easily adjusted through the variation of the thermal annealing temperatures. Electrochemical tests demonstrated that the annealing temperatures had great effects on the electrochemical performances of the obtained composites. The CGN composite annealed at 700 °C exhibited a reversible capacity of 245.2 mAh/g after 100 cycles. Even after it was bent 1000 times, the CGN composite still maintained its superior electrochemical properties. The results suggest that because of its high flexibility and excellent conductive and electrochemical activities, the CGN composites could be used as lithium-ion battery anode materials on a large scale for corresponding applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44727. [ABSTRACT FROM AUTHOR]

The ability of generating arbitrary surface plasmon (SP) profiles in a controllable manner is of particular interest in designing plasmonic imaging, lithography and forcing devices. During the past decades, holography has gained enormous interest and achievements in free-space three-dimensional displays. Here, by applying a two-dimensional version of holography, we experimentally demonstrate a generic method to control the SP profiles. Through controlling the orientation angles of two separated slits under circular polarization incidence, the amplitude and phase of the excited SPs can be freely manipulated, which allows direct generation of the desired SP profiles. A series of controllable SP holography schemes are theoretically and experimentally demonstrated, where the holographic SP profiles with high imaging quality can be dynamically modulated by varying the circular polarization handedness or orientation angle of linear polarization. The universality and simplicity of the proposed design strategies would offer promising opportunities for practical plasmonic applications. [ABSTRACT FROM AUTHOR]

On‐chip wavefront manipulation of terahertz surface plasmons is crucial for the miniaturization and practical application of terahertz technology. Recently, topological metasurfaces have emerged as a promising avenue for spin‐decoupled wavefront manipulation, leveraging the unique topological properties of non‐Hermitian matrices near their singular points. Despite their innovative phase control mechanisms, topological metasurfaces have not yet been explored for surface plasmon devices. Here, spin‐decoupled wavefront manipulation of terahertz surface plasmons is experimentally achieved using freestanding topological metasurfaces. This approach promises to expand the control methods of surface plasmons and broaden the application scenarios of topological metasurfaces, providing a new paradigm for the design of integrated on‐chip terahertz devices. [ABSTRACT FROM AUTHOR]

The responsive hydrogels have received great attention in many fields. However, the molding method and response mode of such hydrogels are criticized when it comes to real applications. In this work, a novel class of poly(N‐isopropyl acrylamide)/graphene oxide (PNIPAm/GO) nanocomposite hydrogel through self‐assembly three‐dimensional (3D) printing via ultraviolet light polymerization. The precursor is ordinarily constituted by NIPAm monomer, crosslinker, and water mixed with a photoinitiator, besides the introduction of nanoclay adjusts the shear thinning properties to an optimal level, which is important for the 3D printing precision. Then, the graphite oxide as infrared light absorber endows the hydrogel fast photothermal excited responsivity instead of conventional temperature response. The shrinkage and swelling of the composite hydrogel can be controlled by turning the near‐infrared light on or off. Meanwhile, the reversible behavior of as‐prepared hydrogel is easily regulated by altering the content of GO and illumination time of near‐infrared light. Additionally, a round tube is obtained based on the as‐prepared hydrogel, which can be driven to get a pencil, indicating their potential applications in actuator and other functional program. [ABSTRACT FROM AUTHOR]

Graphene, as a popular 2D semiconductor, with a carrier concentration that can be extensively tailored by external stimulants, such as electric bias and photoexcitation, is a promising candidate for active optoelectronics. An electrically tunable perfect terahertz absorber is presented by integrating a metallic grating into classical graphene Salisbury screen. The measurement shows that perfect absorption can be achieved for even lightly‐doped graphene and a modulation depth up to 25% is realized. Numerical simulation and analytical model based on the transmission line theory are developed to validate the design, showing a good agreement with the measured results. In addition, dependence of the terahertz response on physical dimensions and polarization of the incident terahertz field is also experimentally explored. It indicates that the hybrid terahertz device is able to function as tunable perfect absorber or tunable polarizer with an extinction ratio up to 23 dB. These results demonstrate the feasibility of using low carrier mobility chemical vapor deposition (CVD) grown graphene for tunable perfect terahertz absorption, which is suitable for potential applications, such as terahertz switching, and time domain and spatial domain modulation. [ABSTRACT FROM AUTHOR]

Planar metamaterials are extensively studied in recent years due to their potential applications in design of flat optical components, ultrasensitive sensors, lasing spasers, and nonlinear devices. Recent studies have reported dynamic control of photoactive material–based metamaterials through optical excitation. However, most of the previous demonstrations rely on single stimulus control and typically require large fluence and ultrafast pulses of light. Here, graphene is integrated with Fano resonant metasurface on silicon substrate that provides active modulation of terahertz waves with low‐power, continuous wave (CW) optical (λ = 532 nm) excitation. More importantly, the hybrid graphene–silicon system provides "dual control" through a combination of applied electrical bias voltage and photodoping of silicon by CW illumination which alters the conductivity of the graphene resulting in an active modulation of the metamaterial resonance. Large real‐time tunability with dual control characteristics of resonant metasurfaces can be a promising route for designing active and functional terahertz metadevices. [ABSTRACT FROM AUTHOR]

In article number 1900237 by Jiaguang Han and co-workers, I N i -fold quasicrystals reveal multiple-direction surface plasmon propagation. By introducing the array factor, three types of tunable on-chip surface plasmon sources based on quasicrystal metasurfaces are achieved. The excited surface plasmon propagation modes can be controlled by the spin-state of the incident light. [Extracted from the article]