ABSTRACT Structural characterization of complex carbohydrates remains challenging. This study employed methylation, acid hydrolysis, 1‐phenyl‐3‐methyl‐5‐pyrazolone (PMP) derivatization, and ultra‐high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) to determine monosaccharides, glycosidic linkages, and sequence of polysaccharides. Combined with matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI TOF MS) and nuclear magnetic resonance (NMR), the structure of two fractions (GEP‐60 and GEP‐60S) obtained from Gastrodia elata Blume was characterized. Both fractions contained mainly glucose, and GEP‐60 was homogeneous polysaccharide (25.5 kDa), while GEP‐60S was mixture of lower molecular weight (DP ≤ 24) fractions. Their primary glycosidic linkage was →4)‐α‐Glcp‐(1→, with respective percentages of 78.41 ± 2.18% and 79.72 ± 1.98%. Sequence analysis identified both contained [→4)Glc(1→]4, [→4)Glc(1→]5, and [→4)Glc(1→]6. NMR confirmed that both polysaccharides possessed main chain composed of →4)‐α‐Glcp‐(1→ and substituted with α‐Glcp‐(1→ branches. Taken mass spectrometry and NMR spectroscopy results together, polysaccharides in G. elata Blume were α‐1,4‐glucan with different molecular weight containing branches substituted at C‐6, with occasional substitution also observed at the C‐2 and C‐3. These findings provided comprehensive structural insights into G. elata Blume polysaccharides and validated feasibility of UPLC–MS/MS as an alternative strategy for analyzing plant polysaccharides.

In this paper, D-type single-core fiber optic sensors and dual-core sensors based on surface plasmon resonance are devised with the purpose of comparatively exploring the characteristics of the single- and dual-core models. There is a plane that is thrown out on the surface of the fiber, and we coat this appearance with a layer of silver (Ag), rotating a cyclic distribution of air holes arranged around the PCF core's perimeter. Three strategically positioned apertures beneath the silver film create two leakage windows. This not only avoids the outward diffusion of the energy of the Y-polarized (Y-POL) core modes, but also facilitates the coupling of Y-POL core modes to the silver film via the leakage windows. In this paper, the internal structure of the optical fibre is optimized by adjusting its structural parameters through finite element analysis and observing the sensing characteristic parameters such as peak loss and half peak width. After obtaining the optimum peak, the sensitivity to refractive index and magnetic field testing is investigated. The sensor utilizes the magnetic field sensitivity properties of magnetic fluids (MF) for magnetic field sensing. Our study shows that such a single-core model of the SPR-PCF sensor can bring about a magnetic field sensitivity of 110pm/mT, while the dual-core one can reach 223pm/mT. Fibre-optic magnetic field sensors are extensively utilized in biomedicine, environmental monitoring, engineering construction and other fields because of their characteristics of not being interfered by electromagnetic radiation, small size and high sensitivity and they play an increasingly pivotal role in modern science and technology and engineering fields.

A tunable terahertz broadband absorber using rectangular and L-shaped coupling is designed. The designed terahertz absorber is a classically three-layer construction with a gold foil as the bottom. The structure mainly consists of an electrically tunable graphene material in the top layer, a dielectric constant SiO 2 with [Formula: see text], a middle sandwich, as well as gold flakes on the bottom layer. The absorption response is realized within the region of 2.81–6.50[Formula: see text]THz with more than 99.9% absorption, and the excellent absorption is obtained at [Formula: see text] [Formula: see text]THz and [Formula: see text] [Formula: see text]THz. The impedance of the receiver is calculated through impedance theory, which perfectly verifies its good absorption frequency band. The influence of the physical parameters in the intermediate layer on the absorber was studied, and the best comprehensive performance was obtained at [Formula: see text]m. Finally, the case of tuning the Fermi level of graphene to [Formula: see text] [Formula: see text]eV by an applied voltage was also studied, and the best absorption was obtained. In general, the absorber exhibits good absorption in the terahertz band. This finding indicates the potential for better application of the absorber in detection. This design has potential for application in optical switches, modulators and energy harvesting, as well as providing more inspiration for the reaction of terahertz broadband absorbers designs.

Wavelength-versatile laser systems play a critical role in the fields of spectroscopy, biomedical, light detection and ranging (LIDAR), precision measurement, and nonlinear frequency conversion. Among the various techniques for realizing this wavelength versatility, crystalline Raman lasers have emerged as a prominent solution. Such scheme overcomes inherent limitations of conventional techniques, including strict phase-matching and spatial hole burning, while offering additional benefits such as beam purification and pulse compression, making them an ideal platform for realizing wavelength-versatile lasers. This article provides a systematic review of the wavelength-versatile crystalline Raman lasers, detailing their operational mechanisms and technological progress in four types of wavelength operation: wavelength-tunable, wavelength-switchable, dual-wavelength, and multi-wavelength. Finally, future development trends are also discussed to offer theoretical references for wavelength-versatile crystalline Raman lasers.

Inflammatory bowel disease (IBD) is closely associated with gut microbiota dysbiosis and systemic manifestations. Pectic polysaccharides have recently become a research hotspot because of their therapeutic effects on IBD and safety. Previous in vitro studies indicated that polysaccharide from Gardenia Fructus (GFP) and its enzymatic hydrolysate (GFPE) modulated gut microbiota composition, but their in vivo effect and underlying mechanisms against colitis remained unknown. Therefore, this study investigated the effects of GFP and GFPE on DSS-induced colitis in mice. The results indicated that oral administration of GFP and GFPE significantly reduced the disease activity index and restored the colon length (p < 0.05). In addition, GFP and GFPE increased the number of goblet cells, decreased the levels of pro-inflammatory cytokines, up-regulated the expression of tight junction proteins, enhanced intestinal immunity, and mitigated oxidative stress. Moreover, GFP and GFPE significantly increased the relative abundance of beneficial genera (Akkermansia, Lachnospiraceae, etc.) and decreased the relative abundance of harmful or colitis-associated genera such as Escherichia-Shigella, etc. (p < 0.05), as well as regulated short-chain fatty acid production. Collectively, these findings suggested the protective effects of GFP and GFPE against colitis, providing a scientific basis for their development as novel functional foods.

This study addresses the challenge of achieving high-strength, hermetic bonding for glass microfluidic chips. We systematically investigated key picosecond laser microwelding parameters (pulse energy, scan speed, focal position) to evaluate their effects on the heat-affected zone and bonding strength in fused silica. Optimal conditions for reliable welding were identified, yielding a shear strength above 60 MPa. Furthermore, the technique was integrated with ultrafast laser-induced selective etching to fabricate sealed glass microfluidic devices. The welded chips demonstrated an internal burst pressure over 15 MPa, and functional droplet- generator and Tesla-valve chips were fabricated and validated. This work provides an efficient, all-laser processing route for high-performance glass microfluidic chips.

Optical tweezers have been widely used for manipulating micro-and nanoparticles, yet conventional trapping systems often demand high optical power and complex focusing configurations. In this work, a low-power optical trapping approach is proposed using an all-dielectric slotted dimer metasurface that supports anapole-enhanced near fields. By taking advantage of the non-radiative interference between electric and toroidal dipoles, strong field confinement and steep intensity gradients are obtained, significantly enhancing the optical gradient force. Numerical simulations confirm that 20 nm-radius nanoparticles can be stably trapped at a power density of 120 mu W/mu m2, about one order of magnitude lower than conventional schemes. These findings reveal the physical mechanism of anapole-assisted trapping and offer a promising route for low-power, thermally stable optical manipulation.

Metalens offer distinct advantages over traditional optical lenses in enhancing imaging performance, reducing system size, and optimizing optical system design. This paper presents the design of an achromatic metalens based on the transmission phase principle, which achieves near-diffraction-limited focusing in the 10.75-11.5 mu m wavelength range and attains an average focusing efficiency of approximately 40.88% at the focal plane across the broadband range. The design employs zinc selenide (ZnSe) nano-elliptical cylindrical structures, characterized by high transmission, low optical loss, and moderate refractive index, to construct a detailed phase and transmission database. A particle swarm optimization (PSO) algorithm, enhanced with mutation operations, was then applied to obtain the actual phase configuration of the metalens, closely matching the ideal phase. The proposed achromatic metalens is expected to contribute to the development of more efficient and multifunctional infrared optical systems, with potential applications in thermal imaging, environmental monitoring, and biomedical diagnostics.

Doping strategies play a crucial role in optimizing the optoelectronic properties of CsPbCl3 perovskites, with antimony cation (Sb3+) emerging as a promising dopant due to its ns2 electronic configuration. However, the influence of Sb3+ doping on the photoelectric performance of CsPbCl3 has not been thoroughly investigated. This study employs density functional theory (DFT) to systematically examine the effects of Sb3+ doping on the electronic structure and optical properties of CsPbCl3. Ab initio molecular dynamics simulations confirm the thermodynamic stability of both pure and Sb-doped CsPbCl3 (Sb:CsPbCl3). The introduction of Sb3+ doping generates impurity energy levels within the conduction band, resulting in a downward shift of the conduction band edge, which is characteristic of n-type doping behavior. Charge density difference analysis further underscores the enhanced electron loss capacity in Sb:CsPbCl3. Moreover, Sb3+ doping induces new dielectric peaks and shifts the absorption spectrum to lower energy regions, thereby significantly broadening the light absorption range of CsPbCl3. These results provide critical insights into the doping mechanisms and establish a theoretical foundation for the advancement of Sb: CsPbCl3 in sophisticated optoelectronic devices.

This paper innovatively proposes a broadband solar absorber and thermal emitter with dual-function integration, achieving breakthroughs in the fields of photothermal conversion and high-temperature thermal emission through three core innovations. First, it integrates high-temperature-resistant metal titanium (Ti) and semiconductor indium arsenide (InAs) into a gradient-like pyramid structure for the first time-this design breaks the limitations of single-material systems (InAs has a narrow intrinsic absorption bandwidth, and pure Ti suffers from insufficient radiation stability). Second, a novel triple-resonance mechanism is developed to realize multi-scale light manipulation: Mie resonance at the pyramid apex enables high-efficiency absorption of ultraviolet-near-infrared (UV-NIR) light, Fabry-Perot cavities in the gaps trap mid-infrared light, and plasmonic-semiconductor coupling at the Ti/InAs interface achieves a 3-5-fold enhancement of the local electric field. Third, the symmetric structure ensures polarization independence and incident angle insensitivity, addressing the issue of performance degradation of traditional absorbers under oblique incidence. Finite Difference Time Domain (FDTD) simulations combined with preliminary experimental verification confirm the excellent performance of this design: the broadband average absorption rate in the 280-3000 nm range reaches 99.06 %, and the weighted average absorption efficiency under AM1.5 conditions is 99.02 % with a solar energy loss of only 0.98. It maintains high radiation efficiency at high temperatures: 97.15 % at 1000 K and 97.77 % at 1200 K (benefiting from the high-temperature stability of Ti (melting point: 1668 degrees C) and the enhanced high-temperature carrier excitation of InAs). Even when the incident angle increases from 0 degrees to 60 degrees, the weighted average absorption efficiency of transverse electric (TE) waves and transverse magnetic (TM) waves remains >91.05 %, outperforming similar symmetric structure. This study realizes the integration of ultra-broadband absorption, high-temperature stable emission, and angle/polarization insensitivity, providing a new paradigm for high-performance solar energy collection and photothermal conversion systems.

Abstract Plasmonic metamaterials and all-dielectric metamaterials, based on metallic or dielectric nanostructures, can concentrate light into subwavelength regions and manipulate light at nanometre length scales through the collective oscillation of free electrons in a metal (plasmon resonances) or from the oscillation of polarization charges and the circular displacement current that are excited inside dielectric mate¬rial (Mie resonances). However, the plasmonic nanostructures undergo large Joule losses and inevitable thermal heating. The all-dielectric metamaterials may overcome the critical issue of heat dissipation and could bridge the gap between fundamental nanoscience and devices. The dielectric resonance elements can be excited by electric and magnetic Mie resonances, and these Mie-type resonance modes can couple or interfere with each other or with other optical modes. Specially, while the radiation of the electric dipole and toroidal dipole modes are similar and in opposite phases, the total scattering cancelation in the far field is reduced to zero, i. e. non-radiating anapole dark state is generated. By manipulating of interaction of multipolar resonances in structured materials, the new field of all-dielectric resonant meta-optics has achieved rapid development. Here, we review the recent development of anapole dark state in dielectric metamaterials, including excitation, probing, coupling, and manipulation. We further discuss the potential applications of anapole state in nanophotonics. This review provides the new insight of anapole physics for achieving flexible and advanced control of light in dielectric nanostructures at the nanoscale.

The swift pace of industrial growth has significantly increased the demand for renewable and clean energy sources. The efficient use of solar energy, a renewable and clean resource, can significantly advance national development. Enhancing solar energy absorption and utilization efficiency is a crucial research focus due to its current low efficiency. This study introduces a broadband solar absorber utilizing a pyramid structure, with its absorption characteristics simulated via the Finite Difference Time Domain (FDTD) method. The chosen wavelength range spans from 280 nm to 3000 nm. Within the 280 nm to 2097 nm range, the absorber achieves an ultra-high average absorption rate exceeding 99.73 %. In the 280 nm - 3000 nm range, the average absorption rate is higher than 99.55 %.Furthermore, the absorber exhibits an exceptional absorption rate exceeding 99.99 % in the 300 nm - 334 nm wavelength range. Analysis of electric and magnetic fields reveals that the high absorption efficiency is mainly due to propagating surface plasma resonance at the center W pyramid, gap surface plasma resonance between each pyramid, and surface plasma resonance between the W pyramid and the dielectric layer. Additionally, when the temperature reaches up to 1000 K, the absorber demonstrates a thermal radiation efficiency of 95.90 %. Under AM1.5 illumination conditions, absorption within the 280 nm to 3000 nm band surpasses 99.56 %. The absorber maintains high absorption levels across incident angles from 0 degrees to 30 degrees and is insensitive to polarization. The proposed structure offers novel perspectives for the advancement of metamaterial - based solar energy conversion devices.

In high-refractive-index dielectric nanostructure, the Mie resonance become evident, and the destructive interference of the radiation fields from electric and toroidal dipole moments results in the excitation of anapole state, which has the unique optical properties of a dark state and can support the excitation of more diverse optical phenomena, such as the electromagnetically induced transparency (EIT) effect. In this study, we performed numerical simulations of a composite metamaterial consisting of Si nanocubes and gold nanorods. The Au-Si composite structure produces an electromagnetically induced transparency spectrum based on the coupling of the optical dark channel (i. e. anapole state) and bright channel (i. e. localized surface plasmon resonance). By tailoring the surface structure of the dielectric Si cube, the surface charge and current distributions can be modified, and finally, the nonradiative anapole state may be influenced and manipulated. The results show that the modified metal/dielectric metamaterial can realize an electromagnetically induced transparency effect with a transmission of up to 95% and a refractive index sensitivity of 170 nm RIU-1.

Nonradiating modes, originally studied in quantum mechanics and astrophysics, have recently been demonstrated to enable strong electromagnetic field localization at the nanoscale, offering a new degree of freedom for manipulating light-matter interactions. However, current studies predominantly focus on individual types of nonradiating modes, with limited exploration of the cooperative mechanisms between multiple modes. In this work, we design a dumbbell-shaped slotted dielectric metasurface capable of simultaneously exciting both anapole and BIC optical modes. Through a comprehensive analysis of near-field and far-field responses, we elucidate the underlying physical mechanisms of these two modes. Moreover, by adjusting the polarization angle of the incident light, anapole resonances distributed along different directions can be selectively excited. Consequently, this enables optical switching with high contrast as well as excellent refractive index sensing performance. This study demonstrates a general approach for integrating multiple nonradiative modes with distinct local field characteristics within a single metasurface structure. The cooperative coexistence of these modes provides new design strategies for multi-mode sensing and tunable photonic devices, thereby enhancing the functionality of the metasurface.

This study presents a novel design for a multi-frequency narrowband terahertz absorber utilizing graphene metamaterials. Unlike other graphene-based terahertz absorbers, the proposed structure eliminates the need for graphene patterning, significantly simplifying the fabrication process and enhancing its feasibility for practical applications. The absorber consists of four layers: an Au substrate, a dielectric layer, a graphene layer, and a patterned Au absorption layer. The pattern of the metasurface absorption layer is composed of four rotationally symmetric rectangles and rings, which achieve high absorption performance while eliminating the need for graphene patterning. The simulation results indicate that when the terahertz wave strikes the absorber at a perpendicular angle and the graphene Fermi level is adjusted to 0.1 eV, the absorber achieves near-perfect absorption at five frequencies: 4.4362 THz, 6.4261 THz, 7.1191 THz, 9.1981 THz, and 9.604 THz, with a maximum absorption rate of 99.828 %. By determining the relative impedance of the absorber using the parameter inversion method through simulation, it is observed that the absorber follows the impedance matching theory. Moreover, through the study of the electric field distribution corresponding to the absorption peak, it is found that when the terahertz wave is incident on the absorber, a high absorption effect is produced due to the localized surface plasmon resonance (LSPR) between the Au layer and the graphene layer on the surface, LSPR technology has been widely utilized in applications such as sensors and absorbers. Furthermore, by adjusting the Fermi level of graphene and analyzing the absorption spectrum, it is demonstrated that the Fermi level enables active tunability of the absorber, highlighting its potential value in the field of terahertz smart devices.

In this paper, an ultra-broadband metamaterial perfect absorber with high absorption in the far-infrared range (14-30 mu m) is designed based on the Ti-TiO2-GaAs-Ti structure. The finite-difference time-domain (FDTD) method is applied to calculate its absorption performance and the distribution of electromagnetic field intensity. Firstly, we express the material data and the fitting effect of the FDTD model to enhance the reliability of the model. Then, the absorption curve and the effective impedance diagram of the absorber are shown to illustrate its perfect absorption characteristics and the causes thereof. Subsequently, the distribution of electromagnetic field intensity on the XOY and XOZ planes of the absorber is provided when it is at the resonant wavelength, further clarifying the possible absorption mechanism. The absorption spectra of the absorber under different polarization modes are also given, indicating its polarization insensitivity in absorption. Moreover, we compare the absorption performance of absorbers with different top structures and combinations of dielectric materials, highlighting the superiority of the absorber which suggested in this paper. Finally, by comparing with previous absorbers, the significant advantages of the absorber proposed in this paper from the view of the absorption performance are revealed.

In this paper, we design a near-infrared metasurface perfect absorber. The absorber consists of a substrate, a chromium(Cr) layer and a four-layer nanocirlce array. The chromium(Cr) layer is on the silicon dioxide(SiO2) substrate, and the four-layer nanocircle array on the top, which is composed of silicon(Si), magnesium fluoride (MgF2), chromium(Cr) and gallium(GaAs) nanocircles with the total thickness of 880nm. The absorption is above 0.913 in the absorption band, where the top absorption is 0.991 and the average absorption is 0.963. Due to the fully symmetric structure, the absorber is not affected by polarization. It can be observed that as the angle of incidence varies from 0 degrees to 60 degrees, the average absorption rate of the absorber does not change significantly. This data indicates the structure's extreme insensitivity to the angle of incident light. Our designed near-infrared metasurface perfect absorber is of good absorption performance and great application prospect in optical communication, broadband thin-film thermal emitter, thermal photovoltaic cell and solar cell. In addition, the high absorption performance of the absorber is insensitive to the tolerance of paramaters which is one of the attraction of practical application.

Zero-dimensional (0D) perovskite derivatives A4PbCl6 (A = Li, Na, K, Rb, Cs) are promising for optoelectronic applications due to their unique properties. However, synthesizing pure-phase samples is challenging, and the impact of A-site cation substitution remains less explored. Addressing these challenges, first-principles calculations based on density functional theory (DFT) are employed to investigate the electronic and optical properties of A4PbCl6 perovskite derivatives. The calculations reveal that the substitution of A-site cations not only modifies the lattice parameters but also alters the distribution of the local electrostatic field within the crystal. These changes lead to variations in the electron density around the Cl and A atoms, thereby tuning the electronic structure and optical properties of the system. Specifically, Cs4PbCl6 exhibits the highest extinction coefficient in the ultraviolet (UV) region, indicating enhanced optical activity, while K4PbCl6 shows greater transparency due to its lower extinction coefficient. The results not only elucidate the impact of A-site cation substitution on the properties of 0D perovskite derivatives but also provide essential theoretical insights for the rational design of new optoelectronic materials, particularly for UV detection and transparent applications.

The photonic crystal fiber sensor designed in this paper uses the surface plasmon resonance phenomenon as its basic operating principle. A metal layer is coated over the outside of the sensor to achieve surface plasmon resonance coupling. Finite element analysis is employed to work out design parameters and assess performance. Here, key design parameters such as the gold layer's thickness and the stomatal diameter are analyzed to identify the optimal design configuration; And defined the tolerance coefficient of design parameters in the actual production process. Next, the performance of the sensor was analyzed. The refractive index was measured in the scope of 1.370 to 1.395 with an interval of 0.005, the sensor demonstrated outstanding sensing capabilities, achieved wavelength sensitivity of 36,000 nm/RIU, a peak amplitude sensitivity of 142.8 RIU-1, and a resolution of 2.7 x 10-6 RIU. In the end, the sensor was used to identify the existence of cervical cancer cells and manifested high wavelength sensitivity, which confirms its excellent biosensing capability. Thanks to its uncomplicated structure, acute sensitivity, and exceptional resolution, the sensor devised in this study is highly suitable for a vast array of applications in chemical and biomedical detection.