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Published
, Published online: 28 August 2026
, doi: 10.37188/lam.2026.121
Structured illumination microscopy (SIM) doubles the lateral resolution compared with wide-field fluorescence microscopy. However, the fast modulation of structured illumination patterns is typically highly dependent on pixelated digital devices, which suffer from low optical efficiency, self-diffraction noise, and high costs. Here, we present a Sector-Rotational SIM (Sero-SIM), which integrates the modulation of the illumination direction and phase shift into a single sector-rotational transmissive grating, achieving an approximately twofold resolution enhancement at a very low cost and minimal control complexity. Moreover, by incorporating a pyramidal lens into the optical setup, we decouple the sector size from the field of view (FOV), expanding the FOV by more than 13 times. We evaluated the performance of Sero-SIM using high-fidelity imaging of diverse subcellular structures in both fixed samples and live cells. The capability of large-FOV super-resolution imaging endows Sero-SIM with a strong potential for applications spanning multiple spatial scales, from pathological tissues and cell populations to single cells and subcellular organelles. Altogether, Sero-SIM introduces a distinctive and practical approach for SIM implementation.
Microcavity-enhanced optoelectronic fiber photoacoustic spectroscopy for ppb-level trace gas sensing
Published
, Published online: 16 April 2026
, doi: 10.37188/lam.2026.028
Photoacoustic spectroscopy is a highly sensitive analytical technique for trace chemical detection in gaseous and liquid phases. Conventional systems relying on free-space optics face limitations in light-matter interaction efficiency and electronic integration. To address this, we developed a miniaturized, ultrasensitive photoacoustic spectroscopy gas sensor by integrating a thermally drawn multi-material optoelectronic fiber, a T-type resonant photoacoustic cell, and a MEMS microphone at the fiber tip. This system enables amplified light-gas interactions and simultaneous electrical signal acquisition, achieving ppb-level detection within seconds using sub-microliter sample volumes (0.02 mL). By leveraging mass-producible optoelectronic fibers and MEMS technology, this work establishes a new class of optical sensors featuring compact size, ultrahigh sensitivity, environmental robustness, and scalable multiplexed detection capabilities for harsh environments.
Published
, Published online: 22 August 2026
, doi: 10.37188/lam.2026.099
Refractory high-entropy alloys (RHEAs) have attracted considerable interest owing to their excellent mechanical strength and thermal stability. However, their inherent brittleness and low thermal conductivity pose significant challenges for high-precision micromachining at room temperature. Conventional nanosecond lasers (CNL) and wire-electrode cutting inevitably cause severe thermal damage and reduce machining quality. In this study, water-jet guided laser (WJGL) technology was utilised for the precision machining of a carbide-reinforced NbMoTaW RHEA. Benefiting from synergistic ablation, cooling, and debris removal effects, WJGLs enable a much cleaner machining interface with minimal spattering compared with CNL and femtosecond lasers. Notably, WJGLs reduced the heat-affected zone to 298 nm, which was ~99.1% lower than that of the CNL. A minimum drilling taper of 0.014° was achieved, indicating ultrahigh micromachining precision. The material removal mechanism and microstructural evolution were elucidated. This study provides a reliable approach for the precision manufacturing of hard-to-process RHEAs.
Published
, Published online: 22 August 2026
, doi: 10.37188/lam.2026.084
Ultrafast laser processing has emerged as a powerful tool for high-precision 3D microfabrication due to its ability to induce localised structural modifications in transparent materials by non-linear multi-photon absorption. In this study, we demonstrated high-precision parallel laser processing by individual axial control of two laser focal spots using a single focusing lens. The proposed method was based on the divergence focus control (DFC) concept, where the focal spot position along the beam axis in the material volume could be controlled by tailoring the laser beam divergence. Numerical simulations confirmed the influence of the axial shift in response to variations in the laser beam divergence. In addition, ray-tracing propagation combined with vector diffraction theory was used to evaluate the influence of spherical aberrations and partial aperture filling on the focal spot morphology and spatial intensity distribution. Experiments were carried out and the results showed that axial focal shifts exceeding 900 µm were achieved by only using a standard microscope objective with a numerical aperture of 0.4. Furthermore, individual control of the two focal points was attained, allowing parallel laser writing with high precision inside transparent materials. For experimental validation, a pair of parallel patterns with different axial distances was fabricated on photosensitive glass, which exhibited high controllability. This method provides a scalable and compact solution for parallel 3D microfabrication and offers advantages such as reduced costs, ease of operation, and straightforward integration into the existing experimental set-up compared with other conventional focusing strategies.
Published
, Published online: 21 August 2026
, doi: 10.37188/lam.2026.082
Wire-grid polarizers, which consist of a one-dimensional periodic metasurface, are convenient polarising elements used in many optical applications. However, these metasurfaces are still incapable of switching the polarisation state of transmitted light without mechanical rotation. This article presents the design of a switchable wire-grid polariser based on a one-dimensional metasurface composed of the phase-change material Ge-Sb-Te (GST). Using the Fourier modal method and genetic-algorithm-based optimisation, we designed a metasurface that transmits two orthogonal linear polarisations of light in different phase states. We demonstrate that the designed metasurface is stable with respect to variations in wavelength and angle of incidence, as well as variations in the geometrical parameters of the metasurface. This concept was verified by measuring the transmission characteristics of a GST metasurface fabricated using magnetron sputtering on a glass substrate. The experimental extinction ratio of the fabricated samples in both polarisation states ranged between 10 and 14~dB, depending on the specific sample. Because the phase transition in GST films can occur on a sub-microsecond timescale, the developed switchable wire-grid polariser offers significant potential for creating a fast, compact polarisation modulator for telecommunication wavelengths.
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.
Published
, Published online: 17 August 2026
, doi: 10.37188/lam.2026.089
High-resolution pixelated patterning of quantum dot colour-conversion (QDCC) layers is of significant importance for advancing display technologies. However, a significant challenge lies in the fabrication of high-resolution pixel templates with submicron precision and geometric uniformity. In this study, a high-precision and scalable femtosecond (fs) laser drilling method is used to fabricate microhole arrays in SU-8 polymers. The results show that, compared with Gaussian beams, Bessel-beam irradiation enables the formation of taper-free microholes with smooth sidewalls and diameters as small as 100 nm, while preventing damage to the underlying glass substrate. The fabricated microholes are used as a micropore mould to fabricate monochrome and dual-colour QDCC layers by precisely filling them with CdSe QDs. These layers exhibit narrow-band fluorescence with full widths at half maximum (FWHMs) of 21 nm (green) and 20 nm (red), high colour purity, and a wide colour gamut reaching 111% of the National Television System Committee (NTSC) standard. Pixel-level photoluminescence (PL) mapping confirms homogeneous emission, with 93% of both red- and green-pixel intensities falling within narrow ranges and luminous uniformities of 90% and 97%, respectively. This maskless and solvent-free process offers a promising platform for high-resolution QDCC layers in augmented reality/virtual reality (AR/VR) systems and next-generation micro-light-emitting diode (micro-LED) displays.
Published
, Published online: 13 August 2026
, doi: 10.37188/lam.2026.093
Precisely separating full-band surface errors is a cornerstone of high-performance optical manufacturing and testing. However, traditional methods rely on subjective frequency band definitions and manual filtering, which leads to inconsistent evaluation standards and introduces analysis errors. Meanwhile, existing data-driven methods mechanically fit noisy manual labels, lacking physical consistency. To address this issue, this paper presents a scale-adaptive physics-aware deep learning framework powered by a dual-domain physics-aware network, which extracts error features by imposing physical constraints in the frequency domain: a specifically shaped spectral domain selective attention mechanism is designed for a low-frequency error with a deterministic spectral envelope; an adaptive learnable spectral gating is designed for mid-frequency error with randomness and anisotropy. Experiments indicate that this network outperforms conventional models under adopted evaluation metrics and exhibits physics-constrained extraction behaviour. This helps mitigate measurement noise and subjective variability introduced by manual filtering, yielding results with improved spectral and physical consistency. Furthermore, it eliminates the reliance on high-performance computing hardware, thereby enabling millisecond-level real-time inference on a standard computer, which greatly facilitates practical engineering deployment. Based on these findings, this study proposes a generalised frequency band division method based on normalised spatial frequency, providing a normalised-frequency-based method for a more consistent cross-scale and cross-instrument frequency band error division.
Design-for-manufacture, fabrication, and assembly of an all-reflective freeform microscope objective
Published
, Published online: 13 August 2026
, doi: 10.37188/lam.2026.113
All-reflective microscope objectives offer distinct advantages for microscopy techniques that operate across widely separated spectral bands. However, designing a high numerical-aperture (NA), unobscured, all-reflective objective that is manufacturable remains a substantial challenge, requiring early integration of fabrication considerations into the optical design process. In this work, we present design-for-manufacture strategies for a 0.65-NA unobscured all-reflective microscope objective enabled by freeform optics. These strategies include minimizing freeform departures, desensitization optimization, and a stray-light analysis. Concepts for mounting and assembly are also introduced and implemented, culminating in the successful fabrication and imaging demonstration of the first system of its kind.
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