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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: 03 June 2026
, doi: 10.37188/lam.2026.034
With the rapid growth of extended-reality (XR) devices, simultaneously achieving long optical path length and miniaturization has become a central challenge in optical system design. One promising approach is to employ optical designs that utilize multiple internal reflections in a prism to extend the path length within a compact volume. The prisms targeted in this study are polyhedral elements composed of three or more optical surfaces including freeform surfaces, in which two lateral faces are mutually parallel. A representative example is a triangular prism whose optical faces are replaced by freeform surfaces. Because such prisms contain multiple reflecting faces, their inter-surface positional relationships must be formed and maintained with high accuracy; consequently, metrology capable of precise evaluation of face-to-face position is indispensable for production. Since 2002, Panasonic has introduced to the market inter-surface misalignment evaluation of lens surfaces using the ultra-high-accuracy three-dimensional profilometer UA3P, contributing to higher-precision camera modules. Building on that platform, the present work develops a new measurement method that extends the UA3P system to prisms with multiple reflecting faces, enabling spatial registration to be evaluated with an accuracy of 0.2–0.3 µm. The developed system shows strong correlation with existing methods and validated repeatability, demonstrating its suitability for high-precision manufacturing and quality assurance of optical elements, including prisms for XR devices.
Published
, Published online: 19 August 2026
, doi: 10.37188/lam.2026.103
Micro-light-emitting diode (micro-LED) displays are prime candidates for near-eye displays, where increasing the panel diagonal at a fixed pixel density is essential to expand the field of view. However, scaling the active area while maintaining luminance homogeneity presents a challenge, primarily due to the pixel-to-pixel current variation in CMOS driven and process-induced non-uniformities in LED arrays. Here we address this trade-off by combining per-pixel current regulation with an optimized fabrication flow in a heterogeneous integration strategy that couples green GaN-based micro-LED with a custom Si CMOS backplane via wafer bonding. The resulting 0.99-inch prototype (1,472 × 1,104 pixels, 14 µm pitch, 1,814 PPI) exhibits >90% brightness uniformity across the active area, peak luminance exceeding 20,000 cd·m−2, a wide viewing angle (>120°), and excellent electrical consistency. These results demonstrate that our heterogeneous integration approach can chart a path toward larger, uniform, and power-efficient micro-displays.
Published
, Published online: 18 August 2026
, doi: 10.37188/lam.2026.091
Micrometre-sized quantum-dot light-emitting diodes (Micro-QLEDs) have been successfully demonstrated as a promising technology for augmented reality (AR) microdisplay applications. To facilitate industrial applications, we developed a two-inch wafer-scale fabrication process for Micro-QLEDs, including the fabrication of a photolithography template, spin-coating fabrication of a QLED, and dicing of a 2-inch wafer into 0.46-inch Micro-QLED panels. Considering the challenge posed by the limited droplet spreading of quantum dots during spin-coating fabrication, we introduced a binary solvent of hexane and octane to achieve a wafer-scale spreading area. In situ high-speed microscopic observations revealed the critical role of Marangoni flow in determining the dynamics of a three-phase contact line. We further designed a 2-inch wafer-scale fabrication process for Micro-QLEDs with an active emitting area of 1,600 mm2, which provides fifteen microdisplay panels with a 0.46-inch Micro-QLED per wafer, achieving a resolution of 2,510 pixels per inch (a pixel size range of 4–50 μm). In addition, the red, green, and blue Micro-QLED wafers had high external quantum efficiencies of 22.8%, 20.8%, and 1.4%, respectively. The 2-inch wafer-scale fabrication process for Micro-QLEDs provides a feasible method for the industrialisation of Micro-QLED technology.
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