Customized spectral response of topological photonic crystal (TPC) structure is of great significance for its practical application. However, the complex spectral response of multimode TPC would make both conventional manual optimization and standard deep learning highly challenging. In this work, we propose a Fourier-encoded deep learning strategy that replaces full-spectrum prediction with frequency-conditioned transmittance prediction. The resulting Fourier MLP resolves sharp spectral variations and achieves high prediction accuracy (R² = 0.9836) across rapidly oscillating transmittance profiles. As a differentiable surrogate, this model effectively guides gradient-based inverse design toward prescribed transmission targets. We validate this approach through two examples: spectral suppression at f=105, 106, and 107 THz; spectral enhancement at f=109 and 112 THz, and suppression at f=110 THz. The proposed method may provide a practical route for the design of complex topological photonic devices, such as filters and sensors.
Helium plasma irradiation is a unique surface modification technique that can induce various surface textures, including self-organized nanostructures, porosity, defects, and compositional changes, on a wide variety of materials. Initially investigated on tungsten mainly in the context of plasma-material interaction for fusion applications, helium-plasma-induced nanostructuring has recently attracted increasing attention as a versatile route for functional surface engineering. In particular, the resulting nanostructured and porous surfaces exhibit strongly altered optical, physicochemical, and electrochemical properties, enabling emerging applications in broadband optical absorbers, light diffusers, photocatalysis, photoelectrochemical water splitting, electrocatalysis, gas sensing, and energy-storage electrodes. This topical review summarizes the fundamentals of helium plasma treatment, including irradiation conditions, morphology evolution, and associated changes in material properties, and then surveys recent progress in application-oriented studies.
Plasma-induced liquid flow is an emerging topic receiving accelerated interest in recent years within the larger inter-disciplinary field of plasma-liquid interactions. The liquid phase transport of reactive oxygen and nitrogen species, plasma produced molecules that have found use in a wide variety of applications, is governed by convective processes. Therefore, controlling the mechanisms that drive plasma-induced liquid flow would lead to control over reactive species transport in liquids, with the potential to thereby improve the efficiency of all plasma-liquid applications. Despite this potential, very little is currently known about the underlying physical processes of plasma-induced liquid flow. This review covers the present limited understanding of the mechanisms behind plasma-induced liquid flow, namely a combination of neutral gas flow, multi-phase electro-hydrodynamic forces, and Marangoni stresses driven by gradients in surface tension. A description is given on the underlying theory behind each of these mechanisms from a general fluid mechanical perspective, along with describing how these mechanisms would arise in plasma-liquid systems. Gaps in the understanding of the fluid mechanics of plasma-liquid interactions are identified and discussed, along with how present and future methods could be used to address these outstanding questions.
In recent years, the demand for DC power supply systems has increased with the widespread adoption of electric vehicles and renewable energy, leading to a growing need for low-cost, highly reliable DC protection devices. A power fuse is a widely accepted choice as a DC protection device; however, conventional arc-quenching media inside the fuse, such as silica sand, exhibit a significant reduction in current-limiting ability in the low-current region, resulting in degraded interruption reliability. In this study, pure water is employed as a new arc-quenching medium to maintain current-limiting performance in the low-current region. Its effectiveness is verified through DC 100 V interruption tests.
Existing multi-polarized transmission–reflection-integrated metasurfaces (TRIMs) usually suffer from fixed or coupled beam power allocation, making it difficult to independently prescribe the beam power ratios in the transmission and reflection spaces. To address this issue, a dual-linearly polarized TRIM with independently prescribed beam power ratios in the two half-spaces is proposed in this paper. The proposed TRIM is based on a quad-channel metasurface unit-cell, which provides two orthogonal transmission channels and two orthogonal reflection channels. By independently rotating the top and bottom patches, the amplitude ratio between the two transmission channels and that between the two reflection channels can be separately controlled, while 1-bit phase compensation is simultaneously maintained. To validate the proposed concept, a TRIM operating at 16 GHz is designed. Four design cases with different beam power ratios are investigated, verifying the independent power allocation capability in the two half-spaces. Furthermore, one representative design case is implemented, fabricated, and measured. The measured results agree well with the simulated ones. This work provides a solution for full-space dual-linearly polarized beam generation with independently prescribed beam power ratios in the two half-spaces, showing potential for bidirectional ground communication scenarios.
