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Published
, Published online: 26 September 2025
, doi: 10.37188/lam.2025.050
In short-wavelength optics, millimetre spot-sized ion beam figuring (IBF) is an effective method to eliminate form errors with spatial wavelengths ranging from 10 mm to 1 mm. In this case, the full width at half maximum (FWHM) of the tool influence function (TIF) is typically below 2 mm. In IBF, accurate measurement of a small-sized TIF is critical in determining the removal rate and distribution. In existing research, the online measurement of the TIF has been achieved by scanning the beam current density (BCD) distribution with the Faraday cup (FC). However, due to the convolution effect during scanning, this method is not sufficiently accurate for small-sized TIFs, posing considerable limitations to high-precision applications. This paper presents an in-depth analysis of the convolution effect in TIF measurements. The obtained findings are applied to a corrective TIF measurement method and verified by calculation, simulation, and experiment. The results demonstrate that the proposed method can effectively reduce the measurement error. Specifically, for TIFs with FWHMs ranging from 0.5 to 1 mm, the average measurement error of the peak removal rate (PRR) is reduced from 47.4% to 3.1%, and the average error in the FWHM is reduced from 51.7% to 2.6%. The application of this method to a polishing experiment reduces the root-mean-square (RMS) of the aspherical optical mirror from 1.7 nm to 0.4 nm; moreover, the average convergence rate is 76.4%, which is within the target spatial wavelength range of 15 mm to 3.6 mm. Thus, this paper provides practical guidance for millimetre spot-sized IBF, and is promising for application in high-precision optics.
Published
, Published online: 22 September 2025
, doi: 10.37188/lam.2025.062
Perovskite nanostructured films are essential to create advanced optoelectronic and photovoltaic devices because of the additional degrees of freedom of manipulation by light reflection and structural colouration, as well as by light trapping and localisation, resulting in control of intensity or polarisation of luminescence. In this paper, we report structural colouration and photoluminescence anisotropy in perovskite films deposited on a substrate with laser-induced periodic surface structures (LIPSSs) on a thin TiO2 layer. The LIPSS TiO2 layer improves charge extraction from the perovskite films, confirmed by a time-resolved photoluminescence analysis. The developed method of substrate nanostructuring does not damage the perovskite films, in contrast to direct laser ablation, imprinting by a mould, mechanical scratching with a cantilever, or plasma-chemical etching. Moreover, the LIPSS formation is appropriate for upscaling owing to the high speed of LIPSS writing (2.25 cm2min-1) and uniform surface nanostructuring.
Published
, Published online: 09 September 2025
, doi: 10.37188/lam.2025.043
In the area of computer-aided optical design most software packages rely on a surface list based data structure. For classical on-axis lenses — such as camera lenses — the list-based data structure is a suitable way for managing lens data. However, for modern high-end optical systems such as off-axis free-form designs, multi-path systems or for accurate tolerance analysis of complex opto-mechanical systems, the list-based approach often reaches its limits. In this paper we present a new tree-like data structure that is able to solve many of the problems that emerge from surface list based data structures.
Published
, Published online: 29 August 2025
, doi: 10.37188/lam.2025.057
Assembling metal nanoparticles into a well-defined array and constructing strongly coupled hybrid systems enable high-quality resonances with narrow linewidths, which offer new opportunities to circumvent the hurdle of plasmonic losses. Herein, we propose a light-driven approach for generating plasmonic arrays by leveraging the self-organized patterns of tightly confined surface plasmon polaritons in single metal nanowires, which exhibit optimized unit structures, tunable interparticle spacings with supra-wavelength or sub-wavelength periods beyond the diffraction limit, and flexible alignment directions. We theoretically and experimentally show the mechanism of generating field patterns via the interplay of a standing wave and optical beating, followed by the formation of periodic geometries under a spatially modulated temperature distribution. We also fabricate plasmonic arrays on microfibres with diameters down to ~1.4 μm and thereby construct a series of hybrid plasmonic–photonic resonators with narrow-band resonances (~3.9 nm linewidth) as well as a barcode system with high multiplexing capacity. Our results show the potential of simple, low-cost, and high-efficiency fabrication of plasmonic arrays and hybrids that may find applications in plasmonic array lasers, information encryption, and high-resolution distributed sensing.
Published
, Published online: 25 July 2025
, doi: 10.37188/lam.2025.039
Perovskite photovoltaics upholds the most prominent position in the field of tandem technology development. In this aspect, the creation of perovskite material with suitable bandgap (≥ 1.65 eV) is necessary. And in order to achieve the best device characteristics, the high-quality film formation is crucial. To get a high-quality film, the solvent engineering approach stays at the forefront. However, although the solvent engineering was well discussed for such conventional material as MAPbI3, the field of wide bandgap perovskite materials is still lacking in this area. This paper presents the solvent engineering approach to improve the efficiency and stability of the conventional wide bandgap perovskite material Cs0.17FA0.83PbI1.8Br1.2. Here we utilize several solvents such as traditional N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and acetonitrile. It was demonstrated that implication of any binary DMF-X solvent improves the solar cell efficiency compared to the pure DMF solution, but the ratio of the X solvent is unique for every X and the foundation for the X influence is also unique. The addition of 2.4 M of DMSO is considered the best to improve the stability and efficiency of laboratory devices, however implementation of AcN allowed to produce 25 cm2 mini-modules with the PCE reaching 10%.
Published
, Published online: 10 July 2025
, doi: 10.37188/lam.2025.033
The largest ground-based telescopes will be much larger than their space-based counterparts far into the future. Remote sensing problems that can take advantage of active and adaptive wavefront control that correct the incoming atmospherically distorted optical wavefront can benefit from very large ground-based telescopes that have other important advantages. For example, their much lower cost (typically one or two orders of magnitude less) and shorter time-to-completion can be compelling. For optical or IR problems that require high angular resolution and large photometric dynamic range we suggest that techniques that make use of photonics, machine learning, or additive manufacturing may even enable less expensive specialized telescopes that are larger than what astronomers are currently building. The Instituto de Astrofísica de Canarias (IAC) recently began a 5 year program with support from the European Union called the Laboratory for Innovation in Opto-mechanics. Its goal is to show how technology innovations can enable less costly and larger telescopes, in particular, aimed at the problem of finding extrasolar life within a few parsecs of the Sun.
Published
, Published online: 04 June 2025
, doi: 10.37188/lam.2025.040
This study proposes a novel heterodyne grating interferometer designed to meet the multi-dimensional atomic-level measurement demands of next-generation lithography systems and large-scale atomic-level manufacturing. By utilizing a dual-frequency laser source, the interferometer enables simultaneous three-degree-of-freedom (3-DOF) displacement measurements. Key innovations include a compact, zero dead-zone optical path architecture, which enhances measurement robustness by minimizing sensitivity to laser source instabilities and atmospheric refractive index fluctuations. In addition, we present a systematic crosstalk error analysis, coupled with a corresponding compensation algorithm, effectively reducing crosstalk-induced errors to below 5%. Experimental evaluation of the 90 × 90 × 40 mm3 prototype demonstrates outstanding performance metrics: sub-nanometer resolutions (0.25 nm for X/Y-axes, 0.3 nm for Z-axis), superior linearity coefficients (6.9 × 10−5, 8.1 × 10−5, 16.2 × 10−5 for X-, Y-, and Z-axes, respectively), high repeatability (0.8 nm@1000 nm for all axes), exceptional long-term stability (20 nm XY-plane drift, 60 nm Z-axis drift over 1000 s), and practical measurement ranges exceeding 10 mm in-plane and 2 mm axially. Comparative analysis with state-of-the-art sensors demonstrates significant advantages in measurement precision, system integration, and multi-axis capability. This advancement highlights excellent potential for applications in integrated circuit fabrication, atomic-scale manufacturing, and ultra-precision metrology for aerospace systems.
Published
, Published online: 29 May 2025
, doi: 10.37188/lam.2025.032
Defect inspection is critical in semiconductor manufacturing for product quality improvement at reduced production costs. A whole new manufacturing process is often associated with a new set of defects that can cause serious damage to the manufacturing system. Therefore, classifying existing defects and new defects provides crucial clues to fix the issue in the newly introduced manufacturing process. We present a multi-task hybrid transformer (MT-former) that distinguishes novel defects from the known defects in electron microscope images of semiconductors. MT-former consists of upstream and downstream training stages. In the upstream stage, an encoder of a hybrid transformer is trained by solving both classification and reconstruction tasks for the existing defects. In the downstream stage, the shared encoder is fine-tuned by simultaneously learning the classification as well as a deep support vector domain description (Deep-SVDD) to detect the new defects among the existing ones. With focal loss, we also design a hybrid-transformer using convolutional and an efficient self-attention module. Our model is evaluated on real-world data from SK Hynix and on publicly available data from magnetic tile defects and HAM10000. For SK Hynix data, MT-former achieved higher AUC as compared with a Deep-SVDD model, by 8.19% for anomaly detection and by 9.59% for classifying the existing classes. Furthermore, the best AUC (magnetic tile defect 67.9%, HAM10000 70.73%) on the public dataset achieved with the proposed model implies that MT-former would be a useful model for classifying the new types of defects from the existing ones.
Dual-modal spatiotemporal imaging of ultrafast dynamics in laser-induced periodic surface structures
Published
, Published online: 14 May 2025
, doi: 10.37188/lam.2025.030
The interactions between ultrafast lasers and materials reveal a range of nonlinear transient phenomena that are crucial in advanced manufacturing. Understanding these interactions during ultrafast laser ablation requires detailed measurements of material properties and structural changes with high temporal and spatial resolutions. Traditional spatiotemporal imaging techniques relying on reflective imaging often fail to capture comprehensive information, resulting in predominantly qualitative theoretical models of these interactions. To overcome this limitation, we propose a dual-modal ultrafast microscopy system that combines two-dimensional reflectivity and three-dimensional topography imaging. By integrating pump-probe techniques with an interferometric imaging system, impressive spatiotemporal resolutions of 236 nm and 256 fs were achieved. Furthermore, using this system, we successfully examined the dynamics of laser-induced periodic surface structure formation, strengthening, and erasure on Si surfaces. The results demonstrate that the dual-modal spatiotemporal imaging technique can serve as a robust tool for the comprehensive analysis of ablation dynamics, facilitating a deeper understanding of the fundamental physics involved and enabling more accurate optimisation of ultrafast laser fabrication processes.
Published
, Published online: 13 May 2025
, doi: 10.37188/lam.2025.035
Surface-enhanced Raman spectroscopy (SERS) is a promising analytical method for studying the structure and composition of multi-component media in clinical practice. However, the practical application of SERS imposes several conditions and restrictions depending on the required analytical accuracy and implementation complexity. This paper proposes a simple serum SERS technique for diagnosing multiple myeloma (MM). The process utilises a substrate composed of agglomerated spherical silver particles (~200 nm) with a capillary effect on sodium nitrate crystals (0.02% volume concentration), excited at a wavelength of 785 nm. Spectral characteristics were recorded using a detector without external cooling, ensuring a cost-effective approach. The proposed low-cost approach was tested on 31 samples from MM and 102 serum samples from an age-matched control group. Combining the SERS technique with the multivariate analysis for serum testing provided high discrimination rates for MM patients compared to the control patients, with an average accuracy of over 96%. Biochemical interpretation of the recorded spectra identified the informative bands at 635 cm-1, 723 cm-1, and 1052 cm-1. Overall, the proposed SERS-based tool can become the basis for screening for MM and can be easily integrated into clinical practice, expanding diagnostic capabilities where expensive laboratory techniques are not affordable.
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