Advanced Optical Materials最新文献

Mid-infrared imaging systems used in gas sensing, thermal diagnostics, and long-range surveillance increasingly demand compact optics capable of both wide-angle coverage and continuous zooming. Conventional refractive or diffractive zoom optics in the mid - wave infrared (MWIR, 3–5µm) band are bulky and difficult to scale, and existing metasurface zoom approaches are typically limited to the visible/NIR regime with narrow fields of view. Here, a mid-infrared Moiré meta-doublet is reported that provides 18× continuous optical zoom (10–180 mm) and >80° diffraction-limited field of view (FOV) using a mechanically simple mutual-angle rotation. The device integrates angle - of - incidence (AOI)-compensated phase synthesis and high-order Moiré polynomial correction to maintain stable point spread functions (PSFs), high Strehl ratios (SRs), and consistent modulation transfer function (MTF) response across the entire zoom range. Imaging demonstrations and USAF-1951 resolution test validate the robustness of the approach for wide-FOV sensing and compact thermal-vision platforms.

The mid-infrared spectral region presents significant potential for sensing and spectroscopic applications. However, traditional plasmonic materials exhibit substantial optical losses within this range, thereby constraining their effectiveness. Emerging materials such as cadmium oxide (CdO) have demonstrated promise in overcoming these limitations. In this work, a novel approach is introduced to engineer large coupling between localized surface plasmons (LSPs) in CdO and localized surface phonon polaritons (LSPhP) in sapphire. By developing a successful dry etching protocol for CdO, stripe arrays with tunable sizes are fabricated, allowing the spectral alignment between the LSP and LSPhP modes. It is demonstrated both experimentally and numerically that when these polaritons become resonant, hybrid modes emerge, resulting in coupling. Finite element simulations reveal near-field enhancements exceeding a factor of 7000, spatially extended hundreds of nanometers around the etched structures. This approach bridges the plasmonic and phononic responses of two mid-IR active materials, paving the way for scalable, high-performance infrared sensing platforms.

Chiral Gold Nanopropellers

The cover features chirally twisted gold “nanopropellers” functionalized with cysteine that couple plasmonic chirality with stereospecific molecular recognition, enabling enantioselective surface-enhanced Raman spectroscopy (SERS) of amino acids. Control experiments, density functional theory (DFT), and finite-difference time-domain (FDTD) simulations confirm a dual mechanism in which handed near-fields amplify selective adsorption, yielding highly sensitive and selective chiral light–matter interactions. More details can be found in the Research Article by Xiao You and co-workers (DOI: 10.1002/adom.202501589).

Laser-Engineered Thermal Metamaterial Platforms

In the Research Article (DOI: 10.1002/adom.202502035), Ufuk Kilic, Mohammad Ghashami, and co-workers present a metamaterial platform based on femtosecond laser surface processing (FLSP) of titanium surfaces. By tuning laser fluence and pulse count, self-organized Ti–TiO_x core–shell mound structures are generated, whose emissivity can be precisely tailored by structural parameters. Combining Mueller matrix spectroscopic ellipsometry and finite element modeling, the study reveals how the engineered structures govern near- and far-field characteristics, activating plasmonic and interband resonance modes across UV to mid-IR wavelengths.

Organic phosphine-based compounds hold important applications in various optoelectronic technologies, including organic light-emitting diodes, X-ray radiation detection, and circularly polarized luminescent materials. A fundamental understanding of their photophysical mechanisms is essential for designing high-performance luminescent systems. In this work, tris(4-chlorophenyl) phosphine (1) and tris(4-chlorophenyl) phosphine oxide (2) are selected as model systems to investigate the mechanism underlying luminescence enhancement. Through in situ high-resolution X-ray single-crystal diffraction under both dark and 360 nm laser irradiation, the experimental charge density distributions of both compounds are precisely characterized. Compared to 1, the P═O group in 2 not only weakens the C─H···π interaction that governs the bandgap, promoting the blueshift of emission, but also introduces strong hydrogen bonding (O···H) that regulates the rates of radiative and nonradiative transitions, considerably enhancing the photoluminescence quantum yield. This dual optimization effect, driven by the strong electronegativity of the electron-withdrawing group, offers an effective avenue of designing high-performance organic deep blue emission materials by selectively tailoring noncovalent interactions.

Lead-free bismuth-based perovskite-inspired materials (Bi-PIMs) are emerging as wide bandgap semiconductors for sustainable optoelectronic applications, including indoor photovoltaics (IPVs). Computational modeling is a powerful tool to understand and optimize their device performance. However, device-relevant thin film optical constants for these absorbers remain scarce, limiting quantitative optical and electrical design. Here, for the first time the optical constants of two promising thin-film Bi-PIMs—Cu₂AgBiI₆ and Cs₃Bi₂I₆Br₃— are determined using spectroscopic ellipsometry. The applied graded effective medium approximation model is supported by the atomic force microscopy and scanning electron microscopy characterizations of varying film thicknesses. A realistic planar device stack is then simulated under both AM1.5G solar and 1000 lx indoor spectra. Under indoor conditions (1000 lx, 4000 K color temperature), the optical photocurrent limits are ca. 91 µA cm⁻² for Cu₂AgBiI₆ and ca. 32 µA cm⁻² for Cs₃Bi₂I₆Br₃ with the corresponding radiative-limit efficiencies of ca. 42 % and ca. 18 %, respectively. These results reveal a significant optical margin and motivate efforts to suppress nonradiative recombination and improve charge transport. More broadly, the extracted optical constants enable accurate photogeneration estimation for optoelectronic device modeling, providing insights into current performance limitations of Bi-PIM devices and guiding strategies to overcome them.

High-performance scintillators are essential for developing the emerging field of nano-scintillation. In this field, scintillation can be enhanced or controlled by nanophotonic structures, making it valuable for medical imaging, radiative detection, and high-energy physics. Multiple-quantum-well structures based on group III-nitride semiconductors are well-known scintillators for flexibility in tuning the emission wavelength. However, they suffer from low radiative efficiency due to the strong quantum-confined Stark effect and high defect density. In this work, a nano-scintillator prepared using low-energy electron beam irradiation (LEEBI) for band engineering is demonstrated. A two-order-of-magnitude increase is achieved in scintillation intensity without any shift in the emission peak. Furthermore, the carrier lifetime is counter-intuitively ten times longer. Using simulations and self-consistent calculations, the results and underlying mechanisms are analyzed. The prominent enhancement of scintillation efficiency suggests new strategies for establishing ultra-low threshold electron-beam-pumped lasers. These findings will not only offer a resolution to the long-standing contradictions surrounding LEEBI, but also push the boundaries of nano-scintillation.

Spatiotemporal metasurfaces offer unique opportunities for wave manipulation; however, their practical realization is often constrained by the requirement for in-plane spatial modulation, which necessitates a large number of time-varying elements. In this work, an alternative architecture based on a cascade of spatially uniform metasurfaces subjected to periodic temporal modulation is introduced. Although all metasurfaces share the same modulation frequency, their individual modulation functions are independently engineered to achieve a desired complex electromagnetic response. A general theoretical framework is developed for the design and optimization of such stacked metasurface systems, composed of dense arrays of cylindrical meta-atoms with time-varying plasma and/or collision frequencies. The effectiveness of the approach is demonstrated through the optimization of metasurface designs that enable magnet-free isolation at the fundamental frequency and a temporal analogue of circulators. Furthermore, it is shown that a metasurface stack can be implemented using only a few time-modulated elements embedded within a parallel-plate waveguide, opening new avenues for extremely compact, versatile, and scalable spatiotemporal platforms for next-generation photonic and microwave systems.

High-power laser-driven projection display demands that the phosphor converters possess excellent thermal handling capacity and stably efficient light output; however, simultaneously enhancing opto-thermal performance is still full of challenges. Herein, a novel universal architecture of phosphor-in-glass film (PiGF) on sapphire substrate with MgO-in-glass (MiG) layer coated on the other side is developed. Owing to the high refractive index of 1.74 and thermal conductivity of 50 W·m⁻¹·K⁻¹ of MgO, the MiG layer not only recycles the backscattering light but also improves the heat dissipation, leading to synergistically enhanced opto-thermal properties of PiGF. Taking Y₃Al₅O₁₂: Ce³⁺ (YAG) PiGF-sapphire-MiG (YSM) as a representative example, the optimized composite enables a high luminous flux (LF) of 5515 lm and luminous efficiency (LE) of 196.9 lm·W⁻¹ at a luminescence saturation threshold (ST) of 28 W·mm⁻². After introducing red-emitting CaAlSiN₃: Eu²⁺ (CASN) component, the YAG-CASN PiGF-sapphire-MiG (YCSM) converter yields warm white light with a color rendering index (CRI) up to 90.6, enabling to realization of more details and more vivid color rendition of the laser projection system. This study provides a cost-effective, easy-prepared, and universal strategy for advancing high-efficiency PiGF-based color converters and high-power laser-driven applications.

Digital Light Processing (DLP)-based 3D-printing offers a fast, energy- and cost-efficient method to fabricate complex plastic scintillators. However, their radiation durability remains uncharacterized, which is crucial for their deployment in high-radiation environments. In this study, the γ-radiation hardness of a DLP-printed plastic scintillator based on Bisphenol A ethoxylate dimethacrylate (BPA), a photocurable monomer with higher aromaticity than conventional monomers such as vinyl toluene (VT) is investigated. The performance of irradiated scintillators is evaluated through pulse height spectra, optical transmission, steady-state and time-resolved photoluminescence (PL), and Shore D hardness. BPA-based scintillators exhibit remarkably higher radiation hardness than VT-based scintillators. Measurements taken 48 h post-irradiation show a decrease of 60% in light yield for VT-based scintillators and 30% for BPA-based scintillators at 20 kGy, revealing a twofold higher retention of light yield by BPA-based scintillators. Transmission losses are found to be 54% for VT-based and 32% for BPA-based scintillators. PL decay profiles remain unchanged in both cases, indicating preservation of fluorophore emission kinetics. Mechanical hardness of VT-based scintillators remain stable, while BPA-based scintillators exhibit slight variations. The findings of this work demonstrate the potential of BPA-based scintillators to establish a new class of radiation-hardened 3D-printed plastic scintillators.