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Published
, Published online: 20 October 2026
, doi: 10.37188/lam.2026.115
Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique for chemical identification that enables trace-level detection across a wide range of applications. However, SERS measurements are typically confined to laboratory environments, requiring a specialised setup and fragile, often single-use, plasmonic substrates. Achieving rugged, reusable SERS measurements, therefore, requires plasmonic substrates with high mechanical robustness and chemical stability. Diamond is an attractive material for this purpose owing to its exceptional mechanical, chemical, and thermal stability and ability to be grown in a laboratory. In particular, it can be used to encapsulate plasmonic nanostructures within a thin film. Robust SERS substrates have been fabricated by encapsulating Ag and Au nanoparticles (NPs) within thin diamond films. Diamond growth conditions control the resulting plasmonic properties, enabling systematic comparison and optimisation of the fabrication parameters. Investigation of Ag- and Au-NPs with diameters of 2−75 nm and diamond film thicknesses of 0 to \begin{document}$ \sim $\end{document}
Published
, Published online: 20 October 2026
, doi: 10.37188/lam.2026.118
We report the theoretical design and experimental implementation of a wideband all-dielectric mirror that preserves the handedness of incident light upon reflection in the near-infrared range. The mirror consists of a high-contrast, near-subwavelength, one-dimensional dielectric grating placed on a Bragg mirror. We optimised this structure using a genetic algorithm and demonstrated its robustness against geometric imperfections and oblique incidences. The experimental reflection spectra measured under normal incidence on a circular-polarisation basis demonstrated a more than 100-nm-wide reflection band, in which more than 98% of the reflected light preserved its handedness. The total reflection coefficient reached 80%. Furthermore, we demonstrated that the fabricated mirror maintains high performance even under oblique incidence for angles up to ±10°. Owing to these unique characteristics, this mirror can serve as a reflective phase plate, making it an excellent candidate for creating Fabry-Pérot resonators for chiral light.
Published
, Published online: 19 October 2026
, doi: 10.37188/lam.2026.092
Arthropods' remarkable ability to maintain clear vision in humid environments, owing to the water-repellent and anti-fogging properties of their compound eyes, provides significant inspiration for advancements in optical imaging technology. Metasurfaces, composed of periodically arranged optical nanostructures on a flat surface, can control the wavefront of incident light, leading to lighter and more compact optical integration. For metasurface, a hydrophobic surface is crucial for ensuring long-term operational stability when exposed to outdoor conditions. While protective or hydrophobic coatings can be integrated into metasurface designs by accounting for their refractive indices during the design phase, such coatings would reduce the refractive index contrast for devices based on low-index materials, which necessitate a substantial increase in the nanostructure height to achieve the required phase modulation, thereby increasing fabrication complexity and aspect-ratio requirements. Here, we introduce a method for fabricating low-cost and highly efficient hydrophobic metasurfaces using high-resolution nanoimprint lithography technology. As a proof-of-concept, the light field control capability of the hydrophobic spiral phase plate is demonstrated, the imaging capability of the hydrophobic metalens in harsh environments is explored, and their potential applications in advanced optical systems are demonstrated.
Published
, Published online: 13 October 2026
, doi: 10.37188/lam.2026.094
Optical absorption is a performance-limiting factor in high-power laser components. This paper reports the deposition of a series of TiO2-Ta2O5 high-reflection (HR) coatings for 1,064 nm wavelength using electron beam ion-assisted deposition (EB-IAD), followed by thermal annealing at temperatures ranging from 473 to 873 K. The experimental results indicated that the annealing temperature significantly influenced the absorption characteristics of the TiO2-Ta2O5 coatings. Unlike the conventional view that absorption is primarily governed by stoichiometry, this study reveals that although the oxygen vacancy concentration decreases with increasing annealing temperature, typically leading to reduced absorption, the absorption of the coating actually increases beyond a certain annealing temperature threshold. This indicates that factors other than the oxygen vacancies also influence the absorption properties of the film. By combining experimental characterisation, molecular dynamics simulations, and ab initio calculations, we propose that the increase in absorption at higher annealing temperatures is closely connected to structural changes in the coating, particularly localised crystallisation and phase separation within the amorphous TiO2-Ta2O5 film. At the optimal annealing temperature, an HR mirror fabricated using the EB-IAD method exhibited an absorption as low as 1.3 ppm. This work not only deepens the understanding of the absorption mechanisms in composite oxide laser films, but also offers new insights and solutions for the low-cost, large-scale production of high-power laser components.
Published
, Published online: 10 October 2026
, doi: 10.37188/lam.2026.097
Recent advancements in smart manufacturing demand wireless power transfer (WPT) systems with dynamic adaptability and miniaturised receivers; however, existing solutions suffer from narrow operational bandwidths and inflexible spatial energy distributions. In this paper, we present a digital metasurface-driven WPT platform that synergises surface plasmon-enhanced coupling with advanced low-temperature cofired ceramic (LTCC) microfabrication. The meta-atom is designed with a wideband configuration and optimised via the magnetoelectric dipole coupling theory. This can enable 180° ± 5° phase modulation over a 22% fractional bandwidth (5.0–6.25 GHz) and achieve adaptive impedance matching under varying load conditions. A multi-target WPT system is further demonstrated by integrating a digital metasurface, dynamically controlled in real time via a field-programmable gate array, as the energy source, and employing rectennas as receivers corresponding to multiple target positions. The system enables the dynamic shaping of the electromagnetic energy distribution through beam reconfiguration, thus achieving highly directional pencil beams with millisecond-level reconfigurability. The LTCC-based rectenna, leveraging multilayer plasmonic ceramic structures, can attain an RF-to-DC efficiency of 70.5% at 5.8 GHz within an 18 mm × 18 mm footprint. Thus, it resolves the efficiency degradation in miniaturised receivers. Experimental results demonstrate that, compared with static metasurface schemes, the proposed system can dynamically switch beam angles and the number of targets in real time, significantly enhancing the spatial energy coverage while maintaining full compatibility with 5G NR standards. This system may pioneer a manufacturing-compatible framework for intelligent metasurface-enabled WPT systems in Internet of Things (IoT) applications.
Published
, Published online: 10 October 2026
, doi: 10.37188/lam.2026.110
The continuously increasing demands for high-precision, scalable nanofabrication capabilities motivate the advent of direct-write technologies complementing advanced lithography. Here, we introduce a parallel photonic nanojet (PNJ)-based strategy using microsphere assemblies and angularly scanned, actively tuned femtosecond laser irradiation. By using 5 µm polymer microspheres and 1,030 nm pulses, we generate sub-500 nm PNJs, enabling spatially programmable, ultra-high-density subwavelength patterning on silicon via controlled incidence angles. A key innovation lies in the compensatory laser parameter adjustments, a necessary prerequisite to maintain uniform feature sizes during automated scanning, thus achieving arbitrary nanoscale patterns with a 5 µm pitch. Scalability analysis reveals that mJ-class lasers could parallelize this process across large-area microsphere arrays, producing millions of nanoscale features simultaneously. This approach holds promise for high-throughput, flexible new manufacturing solutions.
Published
, Published online: 30 September 2026
, doi: 10.37188/lam.2026.127
Optical coherence elastography (OCE) is a non-invasive imaging technique for high-resolution assessment of both tissue elasticity and viscoelasticity. Mechanical characterization enhances biomedical imaging by providing functional insights into tissue health beyond structural information alone. Accurate viscoelastic characterization requires estimating shear wave speed (SWS) across multiple frequencies, as dispersion induces frequency-dependent variations in wave speed. In this paper, we introduce a single-shot multi-frequency reverberant OCE (MFR-OCE) approach to enable reliable viscoelastic characterization by simultaneously capturing shear wave dynamics across multiple frequencies. We present the theoretical framework, experimental setup, and validation of MFR-OCE through simulations and experiments on homogeneous gelatin phantoms and one with an inclusion, ex vivo porcine corneas, and ex vivo bovine liver. Simulation results demonstrate that MFR-OCE estimates SWS with errors below 4% compared to ground truth. Phantom experiments show that MFR-OCE and single-frequency OCE yield closely matching SWS estimates, with differences below 3%. Furthermore, frequency-dependent dispersion coefficients observed in both biological tissues and phantoms align with the theoretical viscoelastic power-law model. The gelatin phantoms exhibit a low viscoelastic behavior with a power-law exponent of 0.13, while porcine corneas demonstrate intermediate viscoelastic behavior, with a power-law exponent of 0.33. The bovine liver shows significant frequency dependence, with a power-law exponent of 0.51. These findings demonstrate that MFR-OCE enables comprehensive viscoelastic characterization and is envisioned to provide a foundation for future development of clinically oriented OCE systems.
Published
, Published online: 23 September 2026
, doi: 10.37188/lam.2026.117
Multi-photon polymerization (MPP) is an emerging manufacturing method capable of producing highly detailed, arbitrarily shaped three-dimensional micro- and nanostructures with feature sizes of single elements below 100 nm. MPP conventionally relies on ultrashort pulse laser systems operating at peak powers in the kilowatt to tens of kilowatt regime and with peak intensities in the range of TW/cm2 to achieve sufficient nonlinear absorption. As a novel approach, here we demonstrate that lasers with significantly lower peak powers and lower peak intensities can also be utilized for MPP at high processing speeds, employing a novel monolithically integrated mode-locked diode laser with 30 W peak power, 7.7 ps pulse length, and a 13.2 GHz repetition rate which could achieve peak intensities of 23 GW/cm2. It is conceivable that the lower peak intensity may be partially compensated for by the considerably higher repetition rate. However, whether this type of compensation is applicable is unclear due to the inherent non-linear MPP process, and requires experimental verification in this work. Using this diode laser prototype, complex 3D structures at scan speeds of up to 100 mm/s were fabricated, achieving rapid production without compromising structural detail. Furthermore, the minimum achievable feature size was assessed through single-line scan experiments at various speeds, obtaining voxel dimensions of down to 121 nm in width and 151 nm in height. Our results suggest that diode laser-based MPP systems can deliver competitive processing performance with a more compact, much less complex, and more cost-effective laser source. This advancement paves the way for scalable parallel multi-laser MPP processing and may significantly accelerate the broader adoption of MPP technology.
Published
, Published online: 23 September 2026
, doi: 10.37188/lam.2026.070
Efficient terahertz (THz) wave manipulation is essential for advancing communications, imaging, and security detection. However, conventional THz devices based on natural materials suffer from the issues of bulky size, low efficiency, and narrow bandwidth. Although dielectric metasurfaces offer a promising alternative, their practical applications still face challenges in high-precision manufacturing, particularly for structures with high aspect-ratio (AR) and deep etching depth. Herein, we experimentally construct high-quality silicon meta-devices for THz wave-controls. Guided by the analysis of the potential structural imperfections, we propose an optimized fabrication method based on the Bosch etching technology to address these challenges and create silicon meta-atoms with high AR and vertical sidewall. As a proof-of-concept, we design and fabricate a half-wave plate (HWP) and a quarter-wave plate (QWP) with a maximum AR of 19.2:1 and broad working bands (0.6–0.8 THz and 0.5–0.8 THz). Their polarization conversion ratios (PCRs) can reach 0.915 and 0.99 at approximately 0.73 THz and 0.66 THz, respectively. Furthermore, we experimentally realize a highly efficient and broadband metalens exhibiting the high average focusing efficiency of 85.56% within 0.6–0.8 THz. Our fabrication methodology can be extended to fabricate other high-performance metasurfaces, opening new possibilities for broadband THz applications.
Published
, Published online: 23 September 2026
, doi: 10.37188/lam.2026.100
As semiconductor process nodes advance, the interaction between electromagnetic waves and mask three-dimensional topography becomes increasingly significant. Curvilinear masks with superior process windows are being rapidly adopted, exposing the limitations of existing thick-mask models in accommodating arbitrary curvilinear edges. Therefore, a theoretical framework for the full-chip-scale, rapid modelling of curvilinear thick masks is required. This paper introduces a physically covariant curvilinear thick-mask model based on edge diffraction correction for rapid full-chip layout simulation. The model decomposes the mask response into a thin-mask approximation term and an edge diffraction correction term. Through rigorous mathematical derivation, the diffraction response of the reference mask edges is decomposed into physically meaningful two-dimensional differential edge diffraction kernels. Furthermore, the edge diffraction term of full-chip layouts is efficiently reconstructed via a multi-channel tensor convolution framework, thereby correcting the thin-mask approximation and establishing the curvilinear thick-mask model. Simulation results demonstrated that, compared with finite-difference time-domain benchmarks, the proposed model achieved curvilinear mask near-field root mean square errors below 0.03 while delivering a speed-up of over 2,600 times. Moreover, it provided more than 2× error reduction over traditional Manhattanisation curvilinear models and maintained superior physical covariance. This study is expected to provide robust support not only for efficient and accurate forward modelling in resolution-enhancement techniques, such as inverse lithography technology and source mask optimisation, but also for the optical characteristic fast simulation of metasurfaces and metamaterials.
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