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Published
, Published online: 10 October 2025
, doi: 10.37188/lam.2025.045
Computer-controlled sub-aperture polishing technology is crucial for achieving high-precision optical components. However, this convolution material removal method introduces a significant number of mid-spatial frequency (MSF) errors, which adversely impact the performance of optical systems. To address this issue, we propose a novel controllable spiral magnetorheological finishing (CSMRF) method that disrupts the mechanism of conventional constant tool influence function (TIF) convolution material removal. In this study, we leverage the advantages of a time-varying spacing strategy and theoretically analyse how time-varying spacing, combined with the spiral swing process of the TIF, mitigates MSF ripple errors. The time-varying spacing method highlights the importance of controlling the characteristic frequency, while the CSMRF method demonstrates a smoothing effect on the errors within the MSF band. Our findings confirm that time-varying spacing and spiral swinging have complementary effects in managing MSF errors. Furthermore, by constraining the MSF error and specific frequency error, we identify the optimal combination of adaptive spacing and spiral angle using a genetic algorithm. On this basis, the MSF error is evaluated by combining the characteristic dwell time solution algorithm. Using the inertial confinement fusion optical element as an example, we observe a 99.938% reduction in the amplitude of the PSD curve of the mid-frequency ripple error with a spatial period of 1 mm, while the mid-frequency PSD curve remains within the standard line. Therefore, the proposed method can effectively control the specific MSF error distribution. This variable convolution kernel (TIF) sub-aperture polishing method provides a new idea for full-band cooperative error control.
Published
, Published online: 09 October 2025
, doi: 10.37188/lam.2025.065
The advent of laser-assisted methods for material slicing attracts a particular attention for technologically important materials as silicon carbide (SiC). Using femtosecond lasers, one can locally initiate multiphoton ionization inside SiC, leading to internal material modifications for slicing SiC ingots into individual wafers. However, intense focused light inside SiC suffers from strong nonlinear effects, such as plasma shielding and self-focusing, which limit energy localization and affect the quality of internal modifications. In this research, we employ temporally-shaped ultrafast trains of pulses for semi-insulating SiC crystal modification. These are generated through an engineered stack of birefringent crystals and permitted successfully slicing a SiC wafer. By adjusting laser parameters, we demonstrate improved energy deposition near the laser focal point and find an optimal combination of laser energy (total energy of pulse train: 10μJ) and number of sub-pulses (8 sub-pulses) to achieve thin single-layer modifications and cracks (thickness: 16.5μm). The suppression of pre-focal plasma shielding and improved control for energy deposition inside crystals are confirmed by side-view luminescence microscopy. Ultimately, the benefits from the technique allow a reduction of the modification layer down to 16.5μm, corresponding to an important advancement for low material-loss SiC wafer slicing.
Published
, Published online: 09 October 2025
, doi: 10.37188/lam.2025.034
Thermal protection and comfort are essential for instruments and humans, especially in high-temperature scenarios such as fires and steelworks. Existing thermal protective windows absorb external radiation and heat when exposed to thermal sources, thereby failing to provide thermal comfort to users. Herein, we present a nanophotonic-engineered thermal protective window (NETPW) strategy that incorporates a visible-light transparent broadband directional thermal emitter and a low-emissivity coating into commercial polycarbonate (PC) windows. In comparison to a PC window exposed to a 700 K thermal source at a half-view angle of 50°, the proposed NETPW exhibits remarkable temperature reduction (~77.7 ℃) by reflecting external radiation and enhancing directional radiative cooling. Simultaneously, the NETPW effectively inhibits heat emissions toward users, resulting in a significant improvement in thermal comfort, with a user’s sensible temperature reduction of 57 ℃. Moreover, the NETPW exhibits high visible transparency, high-temperature resistance, scratch resistance, and impact resistance. The seamless integration with existing windows provides a novel approach for controlling thermal emission and optimizing energy exchange.
Published
, Published online: 09 October 2025
, doi: 10.37188/lam.2025.026
Quartz tuning forks have been recently employed as infrared photodetectors in tunable laser diode spectroscopy because of their high responsivities and fast response time. As for all sensitive elements employed for photodetection, the main drawback is the limited bandwidth of their absorption spectrum. For quartz crystals, the high absorptance for wavelengths above 5 µm guarantees excellent performance in the mid-infrared range, that cannot be easily extended in the visible/near-infrared range because of its transparency from 0.2 to 5 µm. In this work, we report on the development of a laser surface functionalization process to enhance the optical absorption of quartz crystals, named hereafter Black Quartz, in the 1-5 µm spectral range. Black Quartz consists of surface modification of quartz crystal by ultra-fast-pulsed-laser-processing to create localized matrices-like patterns of craters on top. The surface modification decreases the transmittance of quartz in the 1-5 µm range from > 95% down to < 10%, while the transmittance above 5 µm remains unchanged. The Black Quartz process was applied on two quartz-tuning-forks mounted in a tunable laser diode spectroscopy sensor for detecting two water vapor absorption features, one in the near infrared and the other one in the mid-infrared. A comparable responsivity was estimated in detecting both absorption features, confirming the extension of the operation in the near-infrared range. This works represents an important and promising step towards the realization of quartz-based photodetector with high and flat responsivity in the whole infrared spectral range.
Published
, Published online: 30 September 2025
, doi: 10.37188/lam.2025.064
Meta-holograms, the computer-generated holograms assisted with nano-structured metasurfaces, promise efficient recording of light at the nanoscale. Adopting the multiplexing principle further bestows meta-holography with superb capacity for information storage and imaging applications. However, conventional meta-holograms mostly employ a single physical dimension to multiplex the holograms with incomplete light modulation, which imposes critical limitations on holography fidelity. To address this challenge, here we propose and experimentally demonstrate multi-dimensional multiplexing meta-holograms using full-modulation dielectric geometric-phase metasurfaces. Such metasurfaces enable simultaneous, independent, and arbitrary control of the amplitude, phase, and polarization of spatial light based on the geometric-phase principle, with broadband properties. Thanks to the full-modulation principle, the metasurfaces enable the meta-holograms to multiplex multiple holographic images with engineered patterns, polarizations, and directions, depending on the particular input and output conditions. Compared with the holograms acquired with incomplete light modulation, the designed meta-holograms not only inspire an accurate high-capacity information integration with low crosstalk and ideal energy uniformity, but can also facilitate complex multi-dimensional optical information broadcasting, anti-counterfeit, and encryption in compact optoelectronic devices. This work provides a full-modulation metasurface strategy for robust and scalable multi-dimensional multiplexing meta-holography.
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%.
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