Advanced deep learning-based strategy for optical inversion engineering of optical coatings.

Optical inversion engineering is crucial for the precise manufacturing of optical coatings. We present a fast-analytical model to generate a set of simulated datasets for training the deep learning model. Subsequently, a deep learning strategy based on the transformer framework for inversing errors in the manufacturing of optical coatings is proposed.

Real-time high-quality single-lens computational imaging via enhancing lens modulation transfer function consistency.

The demand for high-quality, lightweight infrared imaging systems is rapidly increasing. Single-lens computational imaging, combining single-lens with post-processing algorithms, offers a promising solution to miniaturize imaging systems while maintaining performance. However, these post-processing algorithms are typically highly complex, posing significant challenges for real-time reconstruction on a neural network processing unit (NPU) chip.

Two-dimensional negative refraction steering of hybrid polaritons in graphene/twisted bilayer -MoO heterostructures.

Hyperbolic materials have emerged as a powerful medium for manipulating polaritons at deeply subwavelength scales. In the realm of polaritonic applications, -MoO/graphene heterostructures have shown great promise, featuring low-loss, electrically tunable negative refraction, and enhanced focusing and steering capabilities. However, a significant challenge has been the manipulation of the focusing position of hybrid polaritons, which is limited to a line perpendicular to the interface or unable to be manipulated while steering.

Robust laser self-mixing displacement demodulation via continuous wavelet-Hilbert transform for high-precision accelerometer calibration.

The laser self-mixing grating interferometer based on Cr atom lithography gratings has been applied to the primary calibration of accelerometers due to its compact structure, low cost, high accuracy, and direct on-site traceability. However, the high line density of Cr gratings (4700 l/mm) introduces dense outliers in interferometric signals, complicating displacement demodulation via conventional derivative-based methods and causing frequent phase jumps. To address this challenge, we propose a hybrid algorithm integrating the continuous wavelet transform and the Hilbert transform, which enables robust displacement demodulation under high-noise conditions.

Nonlinear real-time correction in homodyne interferometers by multi-area spatial sampling and dimensionality-reduced ellipse fitting.

Homodyne interferometers are susceptible to signal instability, including the amplitude, relative phase, and DC bias of interference signals, which lead to dynamic nonlinear errors that require real-time correction to ensure full-range displacement measurement accuracy. To address these issues, this paper proposes a real-time, non-iterative FPGA-based nonlinear correction method, designed to balance accuracy and computational efficiency. The method employs peak detection to simplify the elliptical fitting matrix and utilizes feature-based segmented sampling to perform reduced-order correction.

High-Sensitivity Analysis of Polycyclic Aromatic Hydrocarbons by Nanodroplet Interfacial Ionization Coupled with Mass Spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) are well-known environmental pollutants with significant carcinogenic potential. The detection of PAHs by mass spectrometry (MS) remains challenging due to their trace contents and extremely low ionization efficiency. The emerging microdroplet-based MS techniques utilize interfacial reactions for the acceleration of chemical reactions and improvement of ionization efficiency, thereby offering high selectivity and sensitivity for complex samples.

Metal-free high-contrast wafer-level step height standards with large height-range based on all-dielectric multilayers.

Wafer-level step height standards with high optical contrast are crucial in order to improve the accuracy of automatic image recognition in integrated circuits inspection instruments. While conventional Si-SiOsingle-layer film step height standards typically employ metal coatings to address low contrast issues at low step heights, this approach can be problematic due to the introduction of metal particle contamination. In this paper, we propose a high-contrast wafer-level step height standard based on silicon-on-insulator (SOI) dielectric multilayers.

Proximity effect correction in electron beam lithography using a composite function model of electron scattering energy distribution.

The proximity effect induced by electron scattering is one of the main factors limiting the development of high-resolution electron beam lithography (EBL) technology. Existing proximity effect correction (PEC) methods often face challenges related to either high computational demands or insufficient accuracy when calculating the point spread function (PSF) of electron scattering. This paper presents a composite model that combines a power function with a Gaussian function to calculate the PSF, where the forward scattering component is described by a power function and the backscattering component is represented by a Gaussian function.

Broadband perfect Littrow diffraction metasurface under large-angle incidence.

Littrow diffraction devices are commonly used in the laser field (e.g., laser resonators and spectrometers), where system integration requires larger incidence angles and perfect broadband efficiency.

Perfect anomalous refraction metasurfaces empowered half-space optical beam scanning.

Metasurface-based optical beam scanning devices are gaining attention in optics and photonics for their potential to revolutionize light detection and ranging systems. However, achieving anomalous refraction with perfect efficiency (>99%) remains challenging, limiting the efficiency and field of view (FOV) of metasurface-based optical beam scanning devices. Here, we introduce a paradigm for achieving perfect anomalous refraction by augmenting longitudinal degrees of freedom arousing a multiple scattering process to optimize symmetry breaking.

High-Speed Sorting of Sub-20 nm Chiral Particles via Toroidal-Enhanced Separated Potential Wells.

Enantioselective sorting at the nanoscale is highly significant in fields such as medical research, material science, and drug development. However, previous studies mainly focus on static chiral particle separation, hindering practical applications. Here, we utilize the synergy between enantioselective potential wells and flow fields to sort nanoparticle enantiomers at a high velocity of 800 μm/s.

Engineering shear polaritons in 2D twisted heterostructures.

Materials hosting polaritons with extreme optical anisotropy enable nanoscale light manipulation, crucial for nanophotonic applications. In particular, hyperbolic shear polaritons (HShPs), featuring asymmetric propagation, axial dispersion, and loss redistribution, arise in low-symmetry materials (e.g.

Energy ratio controlled gate-tuning four-wave mixing in monolayer graphene.

Monolayer graphene, with a gapless conical electronic band structure, demonstrates scale invariance, showing universal linear optical responses. The impacts of this feature on nonlinear optical responses remain unclear. Our work reveals that the gate-tunable difference-frequency four-wave mixing (DFM) responses in monolayer graphene are significantly influenced by the energy ratios between excitation photons.

Optical sorting: past, present and future.

Optical sorting combines optical tweezers with diverse techniques, including optical spectrum, artificial intelligence (AI) and immunoassay, to endow unprecedented capabilities in particle sorting. In comparison to other methods such as microfluidics, acoustics and electrophoresis, optical sorting offers appreciable advantages in nanoscale precision, high resolution, non-invasiveness, and is becoming increasingly indispensable in fields of biophysics, chemistry, and materials science. This review aims to offer a comprehensive overview of the history, development, and perspectives of various optical sorting techniques, categorised as passive and active sorting methods.

Broadband, Wide-Angle, and Versatile Metasurface Illusions with Inverse Synthetic Aperture Radar Imaging.

Generation of controllable illusions has raised widespread interest. Over the past few decades, this field has been revolutionized by the emergence of metamaterials and metasurfaces. However, current efforts utilizing single-layer metasurfaces are limited to simple illusion demonstrations by reproducing electromagnetic field distributions, which also struggle to achieve both broad bandwidths and wide angular ranges.

Metasurface higher-order poincaré sphere polarization detection clock.

Accurately and swiftly characterizing the state of polarization (SoP) of complex structured light is crucial in the realms of classical and quantum optics. Conventional strategies for detecting SoP, which typically involves a sequence of cascaded optical elements, are bulky, complex, and run counter to miniaturization and integration. While metasurface-enabled polarimetry has emerged to overcome these limitations, its functionality predominantly remains confined to identifying SoP within the standard Poincaré sphere framework.

Mechanisms to improve measurement accuracy through differential signaling in homodyne interferometers.

Homodyne interferometers (HIs) utilize differential signaling to reduce common-mode noise and enhance measurement stability. However, their potential to improve measurement accuracy has not been thoroughly investigated. To address this gap, we reveal two unrecognized mechanisms enabled by differential-output signal (DS): self-compensation for odd-order periodic nonlinear error (PNE) and mitigation of PNE caused by ghost reflections.

Observation of non-Hermitian boundary induced hybrid skin-topological effect excited by synthetic complex frequencies.

The hybrid skin-topological effect (HSTE) has recently been proposed as a mechanism where topological edge states collapse into corner states under the influence of the non-Hermitian skin effect (NHSE). However, directly observing this effect is challenging due to the complex frequencies of eigenmodes. In this study, we experimentally observe HSTE corner states using synthetic complex frequency excitations in a transmission line network.

Observation of Intricate Chiral Optical Force in a Spin-Curl Light Field.

Harnessing chiral optical forces facilitates numerous applications in enantioselective sorting and sensing. To date, significant challenges persist in substantiating the holistic complex theorem of these forces as experimental demonstrations employ common light waves (e.g.

Collimated flat-top beam shaper metasurface doublet based on the complex-amplitude constraint Gerchberg-Saxton algorithm.

Collimated flat-top beam shapers primarily consisting of freeform lenses have a wide range of applications and pose challenges in terms of processing and integration when the diameter is less than millimeters. Metasurfaces represent a promising solution to planarize optics, can mimic any surface curvature without additional fabrication difficulty, and are suitable for flat-top optics. The conventional metasurface design approach relies on imparting the required phase using meta-atoms and encounters challenges in amplitude modulation due to near-field coupling and varying transmittances among meta-atoms with different phases, making the design of flat-top beam shapers difficult.

Nonlinear optics of graphitic carbon allotropes: from 0D to 3D.

The dimensionality of materials fundamentally influences their electronic and optical properties, presenting a complex interplay with nonlinear optical (NLO) characteristics that remains largely unexplored. In this review, we focus on the influence of dimensionality on the NLO properties of graphitic allotropes, ranging from 0D fullerenes, 1D carbon nanotubes, and 2D graphene, to 3D graphite, all of which share a consistent sp hybridized chemical bonding structure. We examine the distinct physical and NLO properties across these dimensions, underscoring the profound impact of dimensionality.

Hybrid topology optimization combining simulated annealing for designing unpolarized high-efficiency freeform metasurface in-coupler for augmented reality waveguide.

High-efficiency in-couplers with unpolarized responses are crucial for the performance of waveguide augmented reality displays. Freeform quasi-3D metasurfaces (FQ3DM), which integrate freeform metasurfaces with multilayer films, is one possible solution to achieve this. However, the performance of FQ3DM is limited by the lack of inverse design algorithms capable of optimizing its overall structure.

High performance LaAlF nanocomposite coatings prepared by a co-evaporation technique.

LaAlF nanocomposite coatings with various amounts of AlF in LaF were deposited on the fused silica substrate using double-source electron beam co-evaporation. The effects of the material composition on the chemical composition, optical properties, microstructure properties, and residual stress of these deposited coatings were investigated. The results showed that although the doping of AlF led to a reduction in the refractive index, the overall performance of the nanocomposites showed remarkable improvement.

Hybrid design scheme for enabling large-aperture diffractive achromat imaging.

Diffractive achromats (DAs) combined with image processing algorithms offer a promising lens solution for high-performance ultra-thin imagers. However, the design of large-aperture DAs that align seamlessly with image processing algorithms remains challenging. Existing sequential methods, which prioritize focusing efficiency in DAs before selecting an algorithm, may not achieve a satisfactory match due to an ambiguous relationship between efficiency and final imaging quality.