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Surface modified ZnS nanoparticles / poly (methylmethacrylate) - (PMMA) nanocomposites were prepared by the solution casting method. The ZnS nanoparticles, as starting materials in the present study, were synthesized mechanochemically and their crystallite size was estimated as 2.3 nm. Surface modification of obtained nanoparticles was performed by 3-Mercaptopropyltrimethoxysilane. We investigate thin samples of the nanocomposite material and pure PMMA (about 290 μm) with a strong interference effect, and corresponding thick samples, as reference. The optical properties of this material were studied by far-infrared spectroscopy. The analysis of the far-infrared reflectivity spectra was made by the fitting procedure, according to the model for a thin plate of nanocomposites in the air. The dielectric function of the nanocomposites was modeled as a mixture of homogenous surface modified ZnS spherical inclusions in PMMA, by the Maxwell-Garnet formula. In the case of a PMMA thin sample, intense, well-defined interference was registered in the range of 90 to 200 cm− 1, while significantly weaker and less well-defined interference was registered in the range around 450 cm− 1. In the thin composite sample, in addition to the interference induced by sample thickness, interference induced by the existence of ZnS nanoparticles was also observed, located between the TO and LO phonons of ZnS. This opens the possibility of applying nanocomposites in interferometry. [ABSTRACT FROM AUTHOR]

The development of unique optical materials that provide amplification and lasing in new wavelength ranges is a major scientific problem, the solution of which is becoming the basis for the emergence of new optical technologies, which are primarily targeting the expanding of operating wavelengths in silica glass. In fact, one of the notable advances in the field of fiber optics over the past two decades has been the production of a new type of laser-active fibers (namely bismuth-doped fibers), which has made it possible to cover previously inaccessible (for rare-earth-doped fibers) spectral ranges, in particular O-, E-, S-, and U-telecom bands. The advance in this direction has led to further growth of the technological capabilities in the telecom industry for amplification and generation of optical radiation in various wavelength bands, which will result in the near future to overcoming the problem known as "capacity crunch" by means of expanding the data transmission range. Recently, bismuth-doped fibers have been actively studying in order to improve their characteristics, which would allow for efficient implementation of optical devices based on bismuth-doped fibers (BDFs) with deployed telecommunications systems. This is one of the dynamically developing areas, where progress has already manifested in form of emergence of new achievements, in particular commercially available various types of BDFs, as well as a series of novel fiber-optic amplifiers for the O- and E-bands. In this review, a number of scientific studies that have already led to a noticeable progress in the field of optical properties of BDFs and the practical implementation of optical devices (lasers and amplifiers) based on them are presented and discussed, with much attention to the achievements of recent years. [ABSTRACT FROM AUTHOR]

Current trends in the development of materials for optics and laser technology were analyzed. The prospects of creating passively Q-switched Yb-Er glass lasers with eye-safe emission wavelengths based on glass-ceramic magnesium aluminosilicate materials for compact pulsed lasers were established. The main types of transparent glass-ceramic materials were analyzed and the main criteria for the synthesis of transparent nanostructured glass-ceramic materials with a crystalline phase content of approximately 70-80 vol.% were substantiated. Compositions of magnesium aluminosilicate glasses were synthesized and the differences of compositions with different types of optical transparency were determined, taking into account their thermal prehistory. The mechanism of phase formation and the differences of ΣMgO, Al2O3, MgO/Al2O3 and ΣRO2 in their composition, which determine the character of crystallization, optical transparency and density under the conditions of heat treatment with a duration of 0.5 and 6 hours, were studied. The developed magnesium aluminosilicate glasses can be used as a basis for the creation of protective and functional high-strength nanostructured glass-ceramic materials based on spinel or cordierite with adjustable optical transparency for optics and laser technology. [ABSTRACT FROM AUTHOR]

This article presents a study on the synthesis and character of a new organic-inorganic hybrid [4FBzTPP]2[CuBr4] (1) ([4FBzTPP]+ is 4-fluorobenzyltriphenylphosphinium) by XRD, SEM, FTIR and UV-Vis. The XRD analysis showed that the hybrid 1 belongs to the triclinic space group P21 with b = 8.8600(10) Å, c = 16.4867(17) Å, α = 16.639(2)°, β = 96.342(4)°, V = 2415.6(5) Å3, and Z = 2. The hybrid consists of two [4FBzTPP]+ cations and one [CuBr4]2– anion, and the [CuBr4]2– exhibits a twisted tetrahedral coordination geometry with the average bond length between Cu–Br is 2.393 Å. The 3D network structure of 1 is formed by electrostatic terms and other intermolecular interactions. The hybrid material undergoes a direct optical transition and has energy gap values of 1.66 eV and 2.18 eV, indicating its potential as a semiconductor material for optical research. The hybrid material undergoes a direct optical transition and has energy gap values of 1.66 eV and 2.18 eV, showing that the hybrid material is a potential semiconductor material for optical research. In addition, the compound exhibited good antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Nanomaterials are of tremendous interest because of their numerous uses. The preparation technique and impurity added to nanomaterials have a significant impact on their structure and effectiveness. Hence, we have examined the optical properties of BaSO4 nanoparticles doped with Fe-ions. The effect of Fe-ions concentration on the spectroscopic and non-spectroscopic techniques of BaSO4, were investigated thermogravimetric differential thermal analyzer (TG–DTA), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Field emission scanning electron microscope (FESEM) with energy dispersive (EDS), transmission electron microscope (TEM), and UV–Visible analysis. The crystallite size of as prepared BaSO4 nanoparticles was found to decreased from 63 to 53 nm with the increase in Fe concentration levels. SEM and TEM micrographs showed that all the samples exhibited a spherical and non-spherical like structures. The optical cut off wavelength and band-gap values for pure and Fe-substituted BaSO4 nanoparticles were found to be 4.05–3.97 eV and 4.10–3.81 eV, respectively, according to the UV-DRS spectra. These results suggest that the optical characteristics of these materials are obviously impacted by the increasing Fe concentration. [ABSTRACT FROM AUTHOR]

The high-efficiency preparation of large-area microstructures of optical materials and precision graphic etching technology is one of the most important application directions in the atomic and near-atomic-scale manufacturing industry. Traditional focused ion beam (FIB) and reactive ion etching (RIE) methods have limitations in precision and efficiency, hindering their application in automated mass production. The pulsed ion beam (PIB) method addresses these issues by enhancing ion beam deflection to achieve high-resolution material removal on a macro scale, which can reach the equivalent removal resolution of 6.4 × 10−4 nm. Experiments were conducted on a quartz sample (10 × 10 × 1 mm) with a specific pattern mask using the custom PIB processing device. The surface morphology, etching depth, and roughness were measured post-process. The results demonstrated that precise control over cumulative sputtering time yielded well-defined patterns with expected average etching depths and surface roughness. This confirms the PIB technique's potential for precise atomic depth image transfer and its suitability for industrial automation, offering a significant advancement in microfabrication technology. [ABSTRACT FROM AUTHOR]

Rare earth and barium titanates are useful as ferroelectric, dielectric, and optical materials. Measurements of their thermophysical properties in the liquid state can help guide melt processing technologies for their manufacture and advance understanding of fragile liquids' behavior and glass formation. Here, we report the density, thermal expansion, viscosity, and surface tension of molten BaTi2O5, BaTi4O9, and 83TiO2-17RE2O3 (RE = La or Nd). Measurements were made using electrostatic levitation and droplet oscillation techniques in microgravity, which provide access to quiescent liquid droplets and deep supercooling of 510–815 K below the equilibrium melting points. Densities were measured over 900–2400 K. Viscosities were similar for all four compositions, increasing from ∼10 mPa s near 2100 K to ∼30 mPa s near 1750 K. Surface tensions were 450–490 dyn cm−1 for the rare earth titanates and 383–395 dyn cm−1 for the barium titanates; surface tensions of all compositions had small or negligible temperature dependence over 1700–2200 K. For solids recovered after melt quenching, x-ray microtomography revealed the fracture mechanics in crystalline products and minimal internal porosity in glass products, likely arising from entrapped gas bubbles. Internal microstructures were generally similar for products processed either in microgravity or in a terrestrial aerodynamic levitator. [ABSTRACT FROM AUTHOR]

Photocontrollable luminescent molecular switches capable of changing emitting color have been regarded as the ideal integration between intelligent and luminescent materials. A remaining challenge is to combine good luminescence properties with wide range of wavelength transformation, especially when confined in a single molecular system that forms well-defined nanostructures. Here, we report a π-expanded photochromic molecular photoswitch, which allows for the comprehensive achievements including wide emission wavelength variation (240 nm wide, 400–640 nm), high photoisomerization extent (95%), and pure emission color (<100 nm of full width at half maximum). We take the advantageous mechanism of modulating self-assembly and intramolecular charge transfer in the synthesis and construction, and further realize the full color emission by simple photocontrol. Based on this, both photoactivated anti-counterfeiting function and self-erasing photowriting films are achieved of fluorescence. This work will provide insight into the design of intelligent optical materials. Photocontrollable luminescent molecular switches which combine good luminescence properties with a tunable range of wavelength transformation are rare. Here, the authors report a π-expanded photochromic molecular photoswitch which displays wide emission wavelength variation, high photoisomerization extent, and pure emission color. [ABSTRACT FROM AUTHOR]

The construction of active materials with controllable optical response facilitates the development of advanced photonic devices. However, the achievement of robust active materials with wide wavelength tunable and broadband emission remains a great challenge, mainly due to the fixed energy levels of conventional active dopants and limited inhomogeneous broadening in common hosts. Here, the study proposes that the cluster in the mesoscopic scale of ≈1 nm may break this bottleneck issue and demonstrate a strategy for the management of photon emission by engineering the cluster evolution. The amorphous glass as the host to tailor the characteristic configuration of Te clusters from 1 to 2 nm by control of the topological structures in glass is employed. Impressively, it presents a distinct optical response totally different from the conventional active centers and this enables to construct of active photonic glass with continuously tunable emission from 888 to 1064 nm. More importantly, Te cluster‐activated photonic glass fibers are fabricated and the broadband on‐off gain is successfully achieved. Furthermore, benefiting from the unique tunable emission, novel near‐infrared devices are constructed and their application in imaging is demonstrated. The approach of cluster engineering mediated tunable optical response is believed to bring new opportunities for developing advanced photonic devices. [ABSTRACT FROM AUTHOR]

In this work, a thermally tunable optical resonator operating in the visible wavelength range is reported, which consists of a bilayer structure composed of a thin silver layer and a dielectric coating of [Fe(HB(1,2,4‐triazol‐1‐yl)3)2] switchable spin‐crossover (SCO) molecules. White light is coupled to the resonant structure using a prism and the resulting resonance spectra are investigated as a function of the incident angle and temperature. Switching the SCO molecules from the low‐spin to the high‐spin state gives rise to a substantial blueshift of the resonances reaching up to 30 nm (associated with a reflectance modulation of up to 70%), which can be linked, through transfer‐matrix simulations, to the variation of the optical thickness of the molecular layer. Interestingly, the study demonstrated that the large thermal tunability of the device also gives rise to a photothermal nonlinearity, which can be leveraged for achieving optical limiting applications. Overall, through the present study, it is shown that molecular SCO nanomaterials can be superior to commonly used thermo‐optical switches and well‐established optical phase‐change materials for applications requiring high broadband optical transparency in the visible spectral domain. [ABSTRACT FROM AUTHOR]

Single-crystal germanium, as an excellent infrared optical material, has been widely applied in X-ray monochromators, night vision systems, and gamma radiation detectors. However, how to obtain high-quality optical lenses on their surfaces still faces challenges due to their hard and brittle properties. To this end, this paper proposes the in situ laser-assisted diamond turning (ILADT) process, which is the combination of a laser heating technique and a single-point diamond turning process. The in situ laser heating technique is employed to enhance the surface quality of the workpiece material, while the single-point diamond turning process is utilized to fabricate optical lenses. Experimental results showed that optical lenses with high surface quality were successfully machined. The profile error is 0.135 μm, indicating the high machining accuracy. The surface roughness Sa of the aspheric lens is 0.909 nm, indicating the high machining quality achieved by the proposed ILADT process. Therefore, this study provides an effective approach for producing high-quality optical lenses on single-crystal germanium surfaces, which holds great promise for future applications in the manufacturing of optical lenses with exceptional quality. [ABSTRACT FROM AUTHOR]

To address the issue of crystal aggregation in CaWO 4 -based glass-ceramics under high temperature or prolonged durations, while also aiming to enhance the luminescent properties, a thermoelectric coupling treatment is introduced during the preparation process of glass-ceramics. In this study, the influence of applying an external DC electric field on the nucleation and crystallization was examined. Techniques such as DSC, XRD, and SEM are utilized to investigate the crystal types and microstructure of the glass-ceramics. Furthermore, the luminescent performance under ultraviolet and X-ray is characterized, with PL, PLE, and XEL spectra being measured. The findings reveal that thermoelectric coupling treatment augments the crystallization content, refines crystal distribution, and enhances luminescent properties. The applied DC electric field provides energy for thermodynamic reactions, reduces activation energy for bond breaking, accelerates ion migration, and facilitates crystal nucleation precipitation. Crucially, it induces polarization of Ti and Zr ions within crystal nuclei, generating electrostatic repulsion between nuclei. These effects mitigate crystal aggregation, refine distribution, and amplify crystal count. This underscores the potential of thermoelectric coupling treatment in synthesizing optical materials utilizing glass-ceramics as luminescent base materials, offering insights for similar researches endeavors. [ABSTRACT FROM AUTHOR]

The human cannot detect light with a wavelength exceeding 700 nm, primarily due to limitations in the physiological structure of the human eye. However, in certain specific scenarios, the ability to detect near-infrared (NIR) light proves to be extremely valuable. To attain this desired capability, NIR up conversion nanoparticles (UCNPs) were prepared and doped in the optical lens materials, aiming to obtain a NIR light "visible" optical lens. It is demonstrated that the doping of UCNPs in the optical lens materials does not significantly impact on their mechanical properties, optical properties, surface properties and it exhibits excellent biocompatibility in cell and animal experiments. More importantly, the UCNPs doping can convert NIR light into visible light within the material effectively and stably. The eyes can "see" the NIR light after wearing such UCNPs doped optical lens. Such NIR light visible optical lens could have great potential in actual applications. [ABSTRACT FROM AUTHOR]

Multi‐dimensional force sensing that combines intensity, location, area and the like could gather a wealth of information from mechanical stimuli. Developing materials with force‐induced optical and electrical dual responses would provide unique opportunities to multi‐dimensional force sensing, with electrical signals quantifying the force amplitude and the luminescence output providing spatial distribution of force. However, the reliance on external power supply and high‐energy excitation source brings significant challenges to the applicability of multi‐dimensional force sensors. Here we reported the mechanical energy‐driven and sunlight‐activated materials with force‐induced dual responses, and investigated the underlying mechanisms of self‐sustainable force sensing. Theoretical analysis and experimental data unraveled that trap‐controlled luminescence and interfacial electron transfer play a major role in force‐induced optical and electrical output. These materials were manufactured into pressure sensor with renewable dual‐mode output for quantifying and visualization of pressures by electrical and optical output, respectively, without power supply and high‐energy irradiation. The quantification of tactile sensation and stimuli localization of mice highlighted the multi‐dimensional sensing ability of the sensor. Overall, this self‐powered pressure sensor with multimodal output provides more modalities of force sensing, poised to change the way that intelligent devices sense with the world. [ABSTRACT FROM AUTHOR]

Birefringent materials with high optical anisotropy have been identified as a research hotspot owing to their significant scientific and technological significance in modern optoelectronics for manipulating light polarization. Researchers studying borate systems have discovered that adding p-conjugated units placed in parallel can significantly increase the birefringence of crystalline solids; some examples include [BO3] units, [B2O5] units, and [B3O6] units. However, there are not many borates with strictly parallel configurations of p-conjugated [B2O5] units. In this study, a new bimetallic borate Sr2Cd4(B2O5)3 with near-parallel arrangement of p-conjugated [B2O5] units was discovered. Sr2Cd4(B2O5)3 possesses the maximum number density of [B2O5] units, shortest dihedral angle of [B2O5] units (between the two [BO3]), and largest degree of [CdO6] octahedral distortion among all the currently known Sr-Cd-B-O tetragonal system borates, making it demonstrate a large birefringence of 0.102 at 532 nm. Theoretical analysis proves that p-conjugated [B2O5] anions are the primary source of the large birefringence of Sr2Cd4(B2O5)3. [ABSTRACT FROM AUTHOR]

Reversible upconversion luminescence (RUCL) modification of rare earth ion-doped ceramic based on photochromism has received much attention in favor of expanding its practical applications. However, RUCL modification induced by photochromism usually employs these traditional methods (electric and magnetic fields) to induce bleaching, which limits its practical applications. In this work, a white α-Ba 2 ScAlO 5 : Yb3+/Er3+ (α-BSAO: Yb, Er) was prepared, which exhibits photochromic coloration from white to blue upon stimulation with 254 nm light. The coloration was able to be bleached by light (808 nm) and thermal (275 °C) stimulation, exhibiting reversible photochromism. The α-BSAO: Yb, Er ceramic exhibited good luminescence performance and reversibility under alternating cycles of 254 and 808 nm (or thermal) light stimulation. It suggests that α-BSAO: Yb, Er ceramic is an ideal anti-counterfeiting agent. The α-BSAO: Yb, Er ceramic sheets can be excited by ultraviolet and near-infrared light, and are capable of realizing the reading of optical information recorded on binary photochromic dot arrays. It shows the potential application prospects of α-Ba 2 ScAlO 5 : Yb3+/Er3+ ceramic in the field of optical storage and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Inspired by designing distinguished optical materials, novel organic molecules with ESIPT characteristics have become the hot topic in current research. Dual-m-N,N-dimethylaniline substituted HBO derivative (DNHBO), as a kind of new dual solid-state and solution-state emission (DSSE) emitter, is focused on its excited state dynamics theoretically in this work. Considering four aprotic solvents with different polarities, the solvent-polarity-regulated photo-induced hydrogen bonding interactions and associated ESIPT behaviours are confirmed. Briefly speaking, via comparing and metering the magnitudes of excited-state reaction barriers in different solvents, we claim that nonpolar solvents drive the ESIPT reaction for DNHBO fluorophore. [ABSTRACT FROM AUTHOR]

Atomistic simulation is performed to study the defect properties and spectroscopy in the MgGa2O4 structure. The calculations indicate that the most favorable type of intrinsic defect is generated by the cation antisite defect, in which there is an exchange of positions between Mg2+ and Ga3+ ions. The calculation also indicates that the incorporation of Eu3+ dopant at the Ga3+(2) site is the most energetically favorable. According to a spectroscopic study using the crystal field approach, Eu3+ replaces the Ga3+ site occupying a combination of C4 and C4h symmetries while maintaining the same amount of the non‐null crystal field parameters. This result is important for the reproduction of experimental energy sublevels and ΔE (7F1) manifold splitting. [ABSTRACT FROM AUTHOR]

The use of femtosecond laser radiation pulses is a very important tool used for metals or cell ablation, structural changes of materials optical properties and many other applications. In this light, we investigate on the generation of continuous-waves solitary structures induced by the dynamics of laser radiation propagation in transparent media with passively mode-locked saturable absober. Thus, understanding the characteristic properties of the dynamics of laser radiations turns out to be a pertinent and important step towards the optimization of their uses, as well as enhancement of tecnology. Our model is characterized by a complex Ginzburg–Landau (CGL) equation with a strong nonlinearity. In full nonlinear regime, numerical simulations of the nonlinear equation revealed multi-periodic wave structures which turn out to be multi-pulse trains. When the number of photon K increases, an increase of the Saturation Power influences considerably the pulse train. The results clearly prove the existence of multi-pulse structures and bound-state solitons with strong nonlinearity on-like cubic-quintic and saturable nonlinearities. [ABSTRACT FROM AUTHOR]

Aluminum garnets display exceptional adaptability in incorporating mismatching elements, thereby facilitating the synthesis of novel materials with tailored properties. This study explored Ce3+-doped Tb3Al5−xScxO12 crystals (where x ranges from 0.5 to 3.0), revealing a novel approach to control luminescence and photoconversion through atomic size mismatch engineering. Raman spectroscopy confirmed the coexistence of garnet and perovskite phases, with Sc substitution significantly influencing the garnet lattice and induced A1g mode softening up to Sc concentration x = 2.0. The Sc atoms controlled sub-eutectic inclusion formation, creating efficient light scattering centers and unveiling a compositional threshold for octahedral site saturation. This modulation enabled the control of energy transfer dynamics between Ce3+ and Tb3+ ions, enhancing luminescence and mitigating quenching. The Sc admixing process regulated luminous efficacy (LE), color rendering index (CRI), and correlated color temperature (CCT), with adjustments in CRI from 68 to 84 and CCT from 3545 K to 12,958 K. The Ce3+-doped Tb3Al5−xScxO12 crystal (where x = 2.0) achieved the highest LE of 114.6 lm/W and emitted light at a CCT of 4942 K, similar to daylight white. This approach enables the design and development of functional materials with tailored optical properties applicable to lighting technology, persistent phosphors, scintillators, and storage phosphors. [ABSTRACT FROM AUTHOR]

Amidst the rapid advancements in the fields of photovoltaics and optoelectronic devices, CsPbBr3 nanosheets (NSs) have emerged as a focal point of research due to their exceptional optical and electronic properties. This work explores the application potential of CsPbBr3 NSs in photonic and catalytic domains. Utilizing an optimized hot-injection method and a ZnBr2-assisted in situ passivation strategy, we successfully synthesized CsPbBr3 NSs with controlled dimensions and optical characteristics. Comprehensive characterization revealed that the nucleation environment and thickness significantly influenced the structure and optical performance of the materials. The results indicate that the optimized synthesis method enables control over the lateral dimensions of the nanoparticles, ranging from 9.1 ± 0.06 nm to 334.5 ± 4.40 nm, facilitating the tuning of the excitation wavelength from 460 nm (blue) to 510 nm (green). Further analyses involving photoresponse and electrochemical impedance spectroscopy demonstrated the substantial potential of these NSs in applications such as photocatalysis and energy conversion. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) are nanoscale carbon materials with unique optical properties and biocompatibility. Their applications are limited by their tendency to aggregate or oxidize in aqueous environments. Turning weakness to strengths, CDs can be incorporated with hydrogels, which are three-dimensional networks of crosslinked polymers that can retain large amounts of water. Hydrogels can provide a stable and tunable matrix for CDs, enhancing their fluorescence, stability, and functionality. CDs@hydrogels, known for their ease of synthesis, strong binding capabilities, and rich surface functional groups, have emerged as promising composite materials. In this review, recent advances in the synthesis and characterization of CDs@hydrogels, composite materials composed of CDs and various types of natural or synthetic hydrogels, are summarized. The potential applications of CDs@hydrogels in fluorescence sensing, adsorption, drug delivery, antibacterial activity, flexible electronics, and energy storage are also highlighted. The current challenges and future prospects of CDs@hydrogels systems for the novel functional materials are discussed. [ABSTRACT FROM AUTHOR]

9,9-bis(4-hydroxyphenyl)fluorene (BPF) is a highly structurally symmetric bisphenol with excellent optical properties of low birefringence and high refractive index, however, the glass transition temperature (T g) of its polyester is high (T g>300°C), which makes it difficult to be thermally processed and limits its application. On the other hand, 4,4′-Thiobis (2-methylphenol) (T2MP) has a flexible thioether group, its introduction not only brings high refractive index, but also can appropriately reduce the T g of the polymer. Therefore, by combining the advantages of both of them, we prepared aromatic polyesters with high refractive index and stabilization. This study provides a route that can appropriately reduce T g without loss of refractive index. [ABSTRACT FROM AUTHOR]

The composite MoO 3 / Me MoO 4 (Me = Cu, Ni, Co, Fe, and Mn) ceramics were obtained by standard high-temperature sintering. Their structure was tested using XRD, SEM, EDS, and XPS. The occurrence of two phases was determined. The main MoO 3 phase exhibited an orthorhombic Pnma space group related to the ceramic grain of micrometre size. The second phase was induced by doping with the Me atom. It showed various monoclinic structures and a smaller grain size. The XPS test confirmed the coexistence of the phases, which was reflected in several lines in the patterns. The valence band of the undoped MoO 3 was located ∼3.3 eV below the Fermi level. An additional subband attributed to the Me 3d state was detected within the energy gap. The MoO 3 / Me MoO 4 composites showed a valence band shifted toward the Fermi level and overlapped with the subband, originating from hybridized Mo 4d – Me 3d states. Magnetic susceptibility showed an antiferromagnetic state below ∼20 K for the Ni- and Fe-doped composites. The estimated magnetic moment magnitudes indicated the contribution from Me 2+ and Me 3+ ions that marked the occurrence of oxygen vacancies. Diffuse reflectance spectra exhibited anomalies in the Vis (∼500–650 nm) and the NIR (∼700–850 nm) ranges and tails in the ∼900–1000 nm range. The estimated magnitudes of energy gaps were attributed to defect-induced states. They corresponded to deduced oxygen vacancies (2.05–2.38 eV) and states or subbands induced by the introduced Me atoms (1.34–1.89 eV). Electric dc resistivity temperature dependence showed thermally activated dependence. The estimated activation energy varied from 0.27 eV to 0.58 eV, depending on the doping of the Me atom. The electric features were consistent with the electronic structure determined using XRD and XPS tests. [ABSTRACT FROM AUTHOR]

Expanding gain bandwidth into the L-band for erbium-doped fiber amplifiers (EDFAs) is a crucial strategy to overcome limitations in prevalent C-band focused commercial silica-based EDFAs, significantly boosting optical network transmission capacity. Herein, we synthesized Er3+-doped broadband near-infrared emission tellurite glasses utilizing the melt quenching process, systematically exploring the impact of ZnCl 2 on the glass structure and optical properties. The 82TeO 2 –3Nb 2 O 5 –15ZnCl 2 –3Er 2 O 3 (TNZ15) glass emerged as a standout candidate for broadband amplifiers around wavelength at 1.55 μm. With escalating ZnCl 2 concentration, a discernible red shift in the emission peak wave lines was observed, accompanied by an expansion of the full width at half maximum (FWHM) from 98 nm to 106 nm. Noteworthy characteristics of all samples included exceptional thermal stability and elevated near-infrared (NIR) transmittance. Application of the Judd-Ofelt (J-O) theory facilitated the calculation of J-O parameter intensity, providing deeper insights into the optical behavior of the materials. Finally, the evaluation of TNZ15 planar optical waveguides, employing the vertical top pumping mode of two 980 nm LEDs, encompassed both the C-band (1530–1565 nm) and the L-band (1565–1625 nm). The results underscore the potential of TNZ15 glass as a promising gain material for broadband optical amplifiers and lasers, offering valuable insights into the development of next-generation optical amplification technologies. [ABSTRACT FROM AUTHOR]

Optical materials with a tunable localized surface plasmon resonance (LSPR) are of great interest for applications in photonics and optoelectronics. In the present study, we explored the potential of generating an LSPR band with an ultra-broad range of over 1000 nm in gold nanoparticles (NPs), precipitated through a thermal treatment in ZnO-Al2O3-SiO2 glass. Using optical absorption spectroscopy, we demonstrated that the LSPR band's position and shape can be finely controlled by varying the thermal treatment route. Comprehensive methods including Raman spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy were used to study the glass structure, while computational approaches were used for the theoretical description of the absorption spectra. The obtained results allowed us to suggest a scenario responsible for an abnormal LSPR band broadening that includes a possible interparticle plasmonic coupling effect taking place during the liquid–liquid phase separation of the heat-treated glass. The formation of gold NPs with an ultra-broad LSPR band in glasses holds promise for sensitizing rare earth ion luminescence for new photonics devices. [ABSTRACT FROM AUTHOR]

Exploring the non-Hermitian properties of semiconductor materials for optical applications is at the forefront of photonic research. However, the selection of appropriate systems to implement such photonic devices remains a topic of debate. In this work, we demonstrate that a perovskite crystal, characterized by its easy and low-cost manufacturing, when placed between two distributed Bragg reflectors with an air gap, can form a natural double microcavity. This construction shows promising properties for the realisation of novel, tunable non-Hermitian photonic devices through strong light–matter coupling. We reveal that such a system exhibits double-coupled polariton modes with dispersion including multiple inflection points. Owing to its non-Hermiticity, our system exhibits nonreciprocal properties and allows for the observation of exceptional points. Our experimental studies are in agreement with the theoretical analysis based on coupled mode theory and calculations based on transfer matrix method. [ABSTRACT FROM AUTHOR]

Refractive index measurements have been an important task for a long time because that index plays an essential role in describing the optical properties of a material. Many methods have been developed to perform that task. Some of them use interferometry to achieve high precision. However, these configurations are complicated. Some measure the critical angle using simple structures, but their accuracy is unsatisfactory because it is difficult to judge the exact critical angle with intensity variations. Here, we propose several new schemes based on measuring the polarization change in the total internal reflection. The proposed method has the merits of simple structure and easy incident angle determination that gives the maximum phase change. Additionally, it is possible to find the material dispersion by measuring the wavelength dependence of the polarization ellipticity. Some useful formulas relating the refractive index to the maximum phase change are obtained. This work can provide valuable alternatives for refractive index measurement. [ABSTRACT FROM AUTHOR]

Thermotropic liquid crystals are versatile optical materials that exhibit a state of matter intermediate between liquids and solids. Their properties can change significantly with temperature, pressure, or other external factors, leading to different phases. The transport properties within these materials in different phases are still largely unexplored, and their understanding would enable exciting prospects for innovative technological advancements. High-order harmonic spectroscopy proved to be a powerful spectroscopic tool for investigating the electronic and nuclear dynamics in matter. Here, we report the first experimental observation of high-order harmonic generation in thermotropic liquid crystals in two different phase states, nematic and isotropic. We found the harmonic emission in the nematic phase to be strongly dependent on the relative orientation of the driving field polarization with respect to the liquid crystal alignment. Specifically, the harmonic yield has a maximum when the molecules are aligned perpendicularly to the polarization of the incoming radiation. Our results establish the first step for applying high-order harmonic spectroscopy as a tool for resolving ultrafast electron dynamics in liquid crystals with unprecedented temporal and spatial resolution. [ABSTRACT FROM AUTHOR]

The development of multifunctional materials with optical and electrical properties has become a research hotspot in recent years. In this work, multifunctional 0.935(Bi 0. 5 Na 0. 5 )TiO3–0.065BaTiO3 (BNT–BT)-based ferroelectric ceramics doped with small amounts of CaMAlO4 (M = Dy , Ho) were prepared, and the effect of CaMAlO4 on the electrostrain and photoluminescence properties of the ceramics was studied. The results showed that the CaMAlO4 addition weakened the ferroelectric properties of the BNT–BT matrix, and promoted the improvement of the electrostrain performance. For samples doped with 1.5 mol% CaMAlO4, the unipolar strain S uni reached the largest values, which were 0.33% (M = Dy) and 0.38% (M = Ho) under an electric field of 70 kV/cm, corresponding to a large signal d 3 3 ∗ ( S max ∕ E max ) of 471 pm/V (M = Dy) and 543 pm/V (M = Ho), respectively. In addition, due to the existing Dy 3 + and Ho 3 + luminescent ions, the modified samples exhibited excellent photoluminescence performance, which exhibited bright yellow emission (M = Dy) and green emission (M  = Ho) under the blue excitation. Due to their multifunctional features, these materials have potential applications as "on-off" actuators, optical-electro integration and coupling devices. [ABSTRACT FROM AUTHOR]

Yttrium aluminum garnet (YAG) is a composite crystalline material used as a substrate in various optical applications, especially high-power lasers. It is currently doped with different elements depending on the desired application. This has generated small controversies depending on the fabrication method as well as the doping content. In the present work, a high-purity YAG single crystal was characterized using x-ray photoelectron spectroscopy (XPS) technique. Exploratory spectra, high-resolution spectra for C 1s, O 1s, Y 3d, and Al 2p, and valence band (VB) spectra were acquired. The results showed the presence of yttrium and aluminum oxides with the characteristic stoichiometry of YAG. In addition, the presence of adventitious carbon was detected, without the presence of impurities. [ABSTRACT FROM AUTHOR]

Atomistic simulation is performed to study the defect properties and spectroscopy in the MgGa2O4 structure. The calculations indicate that the most favorable type of intrinsic defect is generated by the cation antisite defect, in which there is an exchange of positions between Mg2+ and Ga3+ ions. The calculation also indicates that the incorporation of Eu3+ dopant at the Ga3+(2) site is the most energetically favorable. According to a spectroscopic study using the crystal field approach, Eu3+ replaces the Ga3+ site occupying a combination of C4 and C4h symmetries while maintaining the same amount of the non‐null crystal field parameters. This result is important for the reproduction of experimental energy sublevels and ΔE (7F1) manifold splitting. [ABSTRACT FROM AUTHOR]

Lead trihalide PeNPLs (perovskite nanoplatelets) have attracted attention as next‐generation optical materials owing to their excellent properties. Herein, we report quantum‐confined pure‐blue emissive PeNPLs with superior optical properties and "face‐ down" orientation for high‐performance LEDs (light‐emitting diodes). [ABSTRACT FROM AUTHOR]

Strain engineering, as a powerful strategy to tune the optical and electrical properties of two-dimensional (2D) materials by deforming their crystal lattice, has attracted significant interest in recent years. 2D materials can sustain ultra-high strains, even up to 10%, due to the lack of dangling bonds on their surface, making them ideal brittle solids. This remarkable mechanical resilience, together with a strong strain-tunable band structure, endows 2D materials with a broad optical and electrical response upon strain. However, strain engineering based on 2D materials is restricted by their nanoscale and strain quantification troubles. In this study, we have modified a homebuilt three-points bending apparatus to transform it into a four-points bending apparatus that allows for the application of both compressive and tensile strains on 2D materials. This approach allows for the efficient and reproducible construction of a strain system and minimizes the buckling effect caused by the van der Waals interaction by adamantane encapsulation strategy. Our results demonstrate the feasibility of introducing compressive strain on 2D materials and the potential for tuning their optical and physical properties through this approach. [ABSTRACT FROM AUTHOR]

Direct bandgap semiconductors possess a unique attribute: the presence of a free exciton state with a high total oscillator strength. This property makes them highly promising for applications in ultrafast optical signal processing and optical computing. One such protocol for optical computing is based on four‐wave mixing (FWM). In this study, the nonlinear optical effect in polycrystalline thin films of halide perovskite MAPbI3 (MA+ = CH3NH3+$_3^+$) at low temperatures is demonstrated. Through analyzing the spectroscopy of the FWM signal, studying the photoluminescence excitation spectra, and comparing the findings with results from MAPbI3 single crystals, it has been discovered that the strongest nonlinear response is observed at the free exciton resonance and in the region of shallow defect states. Surprisingly, the presence of FWM in cross‐linear excitation geometry has been observed, indicating potential involvement of other nonlinear or many‐body effects. The observations of FWM with free excitons even in highly defective MAPbI3 thin films demonstrate the robustness of the exciton resonance and highlight the practical prospects for utilizing this material in optical computing. [ABSTRACT FROM AUTHOR]

Fluoroborodipyrrole (BODIPY) and Tetraphenylethylene (TPE) are well‐known molecules in the realm of optical materials, celebrated for their exceptional properties. Recent research increasingly focuses on their combined use. In this study, a novel non‐synthetic method is taken to harness the synergistic therapeutic potential stemming from intermolecular interactions by employing nanoparticle encapsulation and core–shell structure. In vitro and in vivo experiments results show that the nanoparticles encapsulating BODIPY and TPE exhibit low cytotoxicity, efficient antitumor properties, and excellent visualization, achieving remarkable 1+1>2 effects. This innovative method not only provides high therapeutic efficacy, but also reduces time and economic costs, providing a novel perspective for exploring the combination of BODIPY and TPE as well as similar molecules in the field of optical materials. [ABSTRACT FROM AUTHOR]

Given the ever‐increasing demand for transmission capacity in optical fiber communication systems, there is a growing focus on developing active fibers and devices with an optical response across a wider spectrum. Bismuth (Bi)‐doped photonic glasses have attracted significant interest for their exceptional ultra‐broadband optical response, particularly within telecommunication bands. However, developing advanced Bi‐activated materials with robust optical response, high compatibility with commercial transmission systems, and low processing temperature remains a huge challenge. Herein, an anion hybridization strategy is proposed to overcome the aforementioned limitations. The anion hybridization significantly enhances the broadband optical response (≈10 times) of the Bi center following the introduction of fluorine ions, and reduces the transition temperature of the photonic glass (≈200 °C). Moreover, the near‐infrared optical response bandwidth experiences significant broadening, a result attributed to the larger inhomogeneous broadening. Furthermore, successful fabrication of the anion‐hybridized Bi‐activated glass fiber is achieved, demonstrating excellent compatibility with commercial transmission fibers. Additionally, the fabricated fiber exhibits an amplified spontaneous emission and on‐off gain across a broad waveband, further validating its efficacy. These results indicate that anion hybridization offers an effective strategy to optimize the optical and thermal properties of photonic materials to develop novel advanced photonic devices. [ABSTRACT FROM AUTHOR]

In recent years, numerous efforts have been devoted to exploring innovative micro/nano‐optical devices (MNODs) with reconfigurable functionality, which is highly significant because of the progressively increasing requirements for next‐generation photonic systems. Fortunately, phase change materials (PCMs) provide an extremely competitive pathway to achieve this goal. The phase transitions induce significant changes to materials in optical, electrical properties or shapes, triggering great research interests in applying PCMs to reconfigurable micro/nano‐optical devices (RMNODs). More specifically, the PCMs‐based RMNODs can interact with incident light in on‐demand or adaptive manners and thus realize unique functions. In this review, RMNODs based on phase transitions are systematically summarized and comprehensively overviewed from materials, phase change mechanisms to applications. The reconfigurable optical devices consisting of three kinds of typical PCMs are emphatically introduced, including chalcogenides, transition metal oxides, and shape memory alloys, highlighting the reversible state switch and dramatic contrast of optical responses along with designated utilities generated by phase transition. Finally, a comprehensive summary of the whole content is given, discussing the challenge and outlooking the potential development of the PCMs‐based RMNODs in the future. [ABSTRACT FROM AUTHOR]

The quest for environmentally sustainable materials spans many fields and applications including optical materials. Here, we present the development of light filters using a gelatin-based nanocomposite. Owing to the plasmonic properties of metallic nanoparticles (NPs), strong light-matter interactions, these filters can be customized across the UV-Visible-NIR spectrum. The filters are designed for modular use, allowing for the addition or removal of desired spectral ranges. Moreover, the nanocomposites are composed of biodegradable and biocompatible materials which highlight the intersection of chemistry and ecological awareness for the exploration of new eco-friendly alternatives. These plasmonic gelatin-based filters block light due to the Localized Surface Plasmon Resonance (LSPR) of the NPs and can be tailored to meet various requirements, akin to a diner selecting options from a menu. This approach is inspired by culinary techniques, and we anticipate it will stimulate further exploration of biomaterials for applications in optics, materials science or electronics. Optical filter materials are used across scientific disciplines for imaging or spectroscopy, but inexpensive and eco-friendly alternatives remain underexplored. Here, the authors exploit the localized surface plasmon resonance of metal nanoparticles embedded in edible gelatine for modular light filters working in the ultraviolet to near-infrared range. [ABSTRACT FROM AUTHOR]

Combining π‐conjugated and non‐π‐conjugated groups is an important strategy for synthesizing new nonlinear optical (NLO) crystals. However, the second harmonic generation (SHG) response and optical anisotropy can be limited by improper spatial alignment of these functional groups in the crystal structure. In this work, it is revealed that non‐π‐conjugated [NH2SO3] group acts as both hydrogen bond donor and acceptor, effectively regulating the 2D planar structure formed by π‐conjugated [C4N3H6] groups. The resulting organic–inorganic hybrid crystal C4N3H6SO3NH2 exhibits a strong SHG response (2.5 × KDP), large optical anisotropy (0.233@546 nm), and blue‐violet and green fluorescence near 360 and 520 nm, respectively. This work expands the methodology for creating new NLO crystals through organic–inorganic hybridization, while also showcasing the potential of C4N3H6SO3NH2 as a multifunctional optical material. [ABSTRACT FROM AUTHOR]

The diffusion dynamics of small molecules into polymer entities is crucial for driving their morphology and function, which can be applied to research fields such as optical identification, medical implantation and intelligent sensing platforms. Herein, we demonstrate a nondestructive bright-field imaging strategy to monitor and control the morphology of polymer microspheres by varying the interfacial interaction and diffusion in a penetrant bath. The nanoscale interface movement of single polymer microspheres was tracked and converted into the diameter variation during the swelling event with sub-pixel accuracy, which is consistent with the calculation using Li–Tanaka's kinetic equations. More interestingly, the solvent diffusion dynamics along different directions of one particle are heterogeneous, indicating the non-uniform internal structure of a soft confined assembly. The swelling characteristics of single polymer microspheres can be quantified by this simple imaging strategy, and the transient intermediate swelling states are captured. To model the lifetime and stabilization times of microplastic entities, solvent selectivity and thermodynamic regulation were introduced to obtain the activation energy down to the single micro-entity level. This optical methodology shows capability for decoding the complex diffusion mechanism in polymer entities and provides guidance for the design of drug delivery systems, sensor platforms, and optical responsive materials. [ABSTRACT FROM AUTHOR]

Optical materials have attracted much attention in anti‐counterfeiting applications due to their visualization and multi‐emission modes. However, the unit occupancy predestines the material to only monochromatic emission, inhibiting the application of optical materials in advanced information encryption. Here, a green to yellow to deep‐red phosphor is reported in a Mn2+‐activated garnet compound Ca2YMgScSi3O12: Mn2+ (CYMSS: Mn2+), originating from the abundant lattice sites occupying within the crystal structure by Mn2+ ions. Three different photoluminescence (PL) emission bands peaked at 517, 576, and 720 nm from 4T1 (G) → 6A1 (S) are observed, which are attributed to the substitution of [Sc/MgO6] octahedron and [Ca/YO8] dodecahedron sites by Mn2+ ions, respectively. Hence, tunable emissions from green to deep‐red are realized in single Mn2+ doping by switching the excitation source of ultraviolet (UV)/blue and X‐ray, which can be further regulated by varying the Mn2+ concentration. Multi‐position occupying, color‐tunable light‐emitting materials offer the possibility of more advanced optical information encryption. [ABSTRACT FROM AUTHOR]

The realization of dual‐wavelength Mn2+ upconversion (UC) luminescence that exhibits different thermal responsive behaviors is promising for non‐invasive optical temperature sensing applications. However, it remains challenging to achieve such luminescence of Mn2+ ions. Herein, due to the site preference characteristics of Mn2+, color tunable and dual‐wavelength Mn2+ UC luminescence is achieved in K2NaScF6:Yb3+, Mn2+ by simply adjusting the Mn2+ doping concentration. Structural and spectral analysis as well as theoretical calculations reveal that the green and red UC emissions originate from two kinds of face‐sharing Yb3+‐Mn2+ dimers, which exhibit different luminescence properties, including different emission wavelength, excited state lifetime, full width at half maximum (FWHM), and luminescence thermal stability. This unique dual‐wavelength UC luminescence of Mn2+ provides a new type of fluorescence intensity ratio thermometer with absolute and relative sensitivities of up to 0.018 K−1 and 0.525% K−1, respectively. This work not only demonstrates the potential application of K2NaScF6:Yb3+, Mn2+ material in the field of optical thermometry but also provides new perspectives for designing multi‐band Mn2+ UC luminescence. [ABSTRACT FROM AUTHOR]

With the emergence of autonomous functions in road vehicles, there has been increased use of Advanced Driver Assistance Systems comprising various sensors to perform automated tasks. Light Detection and Ranging (LiDAR) is one of the most important types of optical sensor, detecting the positions of obstacles by representing them as clusters of points in three-dimensional space. LiDAR performance degrades significantly when a vehicle is driving in the rain as raindrops adhere to the outer surface of the sensor assembly. Performance degradation behaviors include missing points and reduced reflectivity of the points. It was found that the extent of degradation is highly dependent on the interface material properties. This subsequently affects the shapes of the adherent droplets, causing different perturbations to the optical rays. A fundamental investigation is performed on the protective polycarbonate cover of a LiDAR assembly coated with four classes of material—hydrophilic, almost-hydrophobic, hydrophobic, and superhydrophobic. Water droplets are controllably dispensed onto the cover to quantify the signal alteration due to the different droplets of various sizes and shapes. To further understand the effects of droplet motion on LiDAR signals, sliding droplet conditions are simulated using numerical analysis. The results are validated with physical optical tests, using a 905 nm laser source and receiver to mimic the LiDAR detection mechanism. Comprehensive explanations of LiDAR performance degradation in rain are presented from both material and optical perspectives. These can aid component selection and the development of signal-enhancing strategies for the integration of LiDARs into vehicle designs to minimize the impact of rain. [ABSTRACT FROM AUTHOR]

In this study, the photoluminescence (PL) behavior of two aluminosilicate glass series containing alkali-niobates ranging from 0.4 to 20 mol% was investigated. The glasses exhibit an intense visible emission centered at ~18,400 cm−1 for the peralkaline series and at higher energies (~19,300 cm−1) for the metaluminous glasses. However, the photoluminescence emission intensity varies significantly with the niobate content and the bulk chemistry. PL and fluorescence lifetime measurements indicate that the broad emission bands result from the overlap of different niobate populations, whose distribution changes with niobate content. The distinct PL behavior in the two glass series was related to the structural evolution of the niobate units upon niobium addition. An enhancement of the visible emission was observed for a higher fraction of distorted [NbO6] units. Eu-doping was carried out as a structural probe of the glass network, and also to determine if these glasses could be used as potential rare earth element (REE) activators. The crystal field strength around Eu ions is strongly dependent on the bulk chemistry and the niobate content. Furthermore, the peralkaline series showed energy transfer from the host [NbO6] to Eu3+, confirming the feasibility of exploring niobate glasses and glass-ceramics as lanthanide ion-activated luminescent materials. In addition, glass-ceramics (GCs) containing alkali-niobate phases with a perovskite-like structure were developed and studied to verify the optical performance of these materials. It was verified that the bulk chemistry influences crystallization behavior, and also the photoluminescence response. The transparent GC from the metaluminous series exhibits a quenching of the Eu3+ emission, whereas an enhanced emission intensity is observed for the peralkaline GC. The latter shows a strong excitation-dependent PL emission, suggesting energy transfer and migration of electronic excitation from one Eu population to another. Additionally, Eu3+ emissions arising from the D 1 5 and D 2 5 excited states were observed, highlighting the low phonon energy achievable in niobo-aluminosilicate hosts. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) possess a considerable number of beneficial features for latent applications in biotargeted drugs, electronic transistors, and encrypted information. The synthesis of fluorescent carbon dots has become a trend in contemporary research, especially in the field of controllable multicolor fluorescent carbon dots. In this study, an elementary one-step hydrothermal method was employed to synthesize the multicolor fluorescent carbon dots by co-doping unique phenylenediamine isomers (o-PD, m-PD, and p-PD) with B and P elements, which under 365 nm UV light exhibited signs of lavender-color, grass-color, and tangerine-color fluorescence, respectively. Further investigations reveal the distinctness in the polymerization, surface-specific functional groups, and graphite N content of the multicolor CDs, which may be the chief factor regarding the different optical behaviors of the multicolor CDs. This new work offers a route for the exploration of multicolor CDs using B/P co-doping and suggests great potential in the field of optical materials, important information encryption, and commercial anticounterfeiting labels. [ABSTRACT FROM AUTHOR]

Optical materials have attracted much attention in anti‐counterfeiting applications due to their visualization and multi‐emission modes. However, the unit occupancy predestines the material to only monochromatic emission, inhibiting the application of optical materials in advanced information encryption. Here, a green to yellow to deep‐red phosphor is reported in a Mn2+‐activated garnet compound Ca2YMgScSi3O12: Mn2+ (CYMSS: Mn2+), originating from the abundant lattice sites occupying within the crystal structure by Mn2+ ions. Three different photoluminescence (PL) emission bands peaked at 517, 576, and 720 nm from 4T1 (G) → 6A1 (S) are observed, which are attributed to the substitution of [Sc/MgO6] octahedron and [Ca/YO8] dodecahedron sites by Mn2+ ions, respectively. Hence, tunable emissions from green to deep‐red are realized in single Mn2+ doping by switching the excitation source of ultraviolet (UV)/blue and X‐ray, which can be further regulated by varying the Mn2+ concentration. Multi‐position occupying, color‐tunable light‐emitting materials offer the possibility of more advanced optical information encryption. [ABSTRACT FROM AUTHOR]

Pressure‐induced emission enhancement (PIEE) is a novel phenomenon in contrast to conventional pressure‐induced emission quenching, and has attracted considerable attention owing to the potential application of materials with this effect as optical pressure‐sensing devices. The urgent need and significant significance lie in the design and exploration of systems that possess high‐efficiency PIEE. Here, a large PIEE in a novel zero‐dimensional (0D) hybrid manganese bromide is realized, (BPPH)2MnBr4·1.5CH3CN [BPPH+ = bis(triphenylphosphine)iminium]. The experimental and theoretical results demonstrate that such emission enhancement is primarily attributed to the pressure‐induced reconfiguration of electronic band alignment and resultant redistribution of band‐edge excitons. Under compression, the electronic bandgap of (MnBr4)2− experiences a more rapid reduction compared to that of the organic cations. Consequently, this leads to the gradual closure of the charge transfer pathway from (MnBr4)2− to BPPH+. This progression results in a higher retention of excitons on (MnBr4)2−, amplifying the efficiency of Mn2+d–d transitions, and leading to a substantial enhancement in emission. This study not only offers fresh insights into the behavior of carrier dynamics induced by pressure in hybrid manganese halides but also presents a promising avenue for the advancement of PIEE systems. [ABSTRACT FROM AUTHOR]

Hydrogel‐based optical waveguides have attracted extensive attention in optogenetics, implantable photomedicine, and biosensors due to their excellent biocompatibility and tissue‐like modulus in compared with traditional SiO2‐based rigid optical fibers. However, the existing ion‐induced supramolecular assembly of alginate‐based hydrogel optical fibers commonly lack of long‐term stability due to poor mechanical property accompanied with swollen. In this paper, a novel catalytic surface polymerization method is developed based on a redox reaction mechanism to in situ grow robust and slippery cladding layer on a core poly(ethylene glycol) dimethacrylate (PEGDA) hydrogel fiber by using the alternative H‐bonding poly(N ‐acryloyl glycinamide) (PNAGA) hydrogels. The resultant hydrogel optical fiber with core‐cladding heterogeneous structure can achieve the desirable total reflection condition, leading to good light transmission and low light loss. The PNAGA cladding with robust H‐bonding network endows the hydrogel optical fiber with high stability and outstanding lubrication in humid environment. More importantly, the hydrogel optical fiber possesses good tissue‐like mechanical performance together with excellent biocompatibility, which shows the great advantages for biomedical applications in compared with traditional glass optical fibers. This work will broaden implantable hydrogel optical fibers in material design and structure processibility, promoting the use of hydrogel‐based optical fibers in various applications. [ABSTRACT FROM AUTHOR]

The indication of information in materials is widely used in our daily life, and optical encoding materials are ideal for information loading due to their easily readable nature and adjustable optical properties. However, most of them could only indicate one type of information, either changing or unchanging due to the mutual interference. Inspired by firefly, we present a non-interfering bipolar information indication system capable of indicating both changing and unchanging information. A photochemical afterglow material is incorporated into the photonic crystal matrix through a high-throughput technique called shear-induced ordering technique, which can efficiently produce large-area photonic crystal films. The indication of changing and unchanging information is enabled by two different utilizations of white light by the afterglow material and photonic crystals, respectively, which overcome the limitations of mutual interference. As a proof of concept, this system is used to indicate the changing photodegradation level of mecobalamin (a photosensitive medicine) and unchanging intrinsic drug information with anti-counterfeiting functionality, which is a promising alternative to instantly ascertain the efficacy of medicine at home where conventional assays are impractical. Inspired by fireflies, a bimodal information indication system using a photochemical afterglow material within a photonic crystal matrix is developed to display both static and changing information, such as sample type and degree of degradation. [ABSTRACT FROM AUTHOR]