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We experimentally demonstrated an all-fiber focused vortex beam (FVB) generator which was prepared by milling a spiral zone plate (SZP) on the Au-coated end face of a hybrid fiber by focused ion beam (FIB). In this generator, the fundamental modes propagating in the hybrid fiber are focused while being modulated into high-order orbital angular momentum (OAM) mode by the SZP at the end face. The focus length and topological charge were designed and then were both theoretically and experimentally verified. The results show that, the obtained characteristics of the FVB agree with the designed ones. The measured diameters of the focal spots are 2.2 µm, 4.4 µm, and 5.2 µm for the FVB with the topological charge of 0, 1, and 2, respectively. The simulated results show that the proposed FVB generators can maintain good focusing characteristics in different liquids, so it is a good candidate for optical fiber spanner use in a complex liquid environment. Moreover, the processing efficiency of the proposed FVB generators is nearly ten times higher than that of the previously reported ones due to the Au-coated film.
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http://dx.doi.org/10.1364/OL.465949 | DOI Listing |
Microsyst Nanoeng
September 2025
Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, and the Key Laboratory of Optoelectronics Information and Technology (Ministry of Education), Tianjin University, Tianjin, 300072, China.
Terahertz communication systems demand versatile devices capable of simultaneously controlling propagating waves and surface plasmon polaritons (SPPs) in far-field (FF) and near-field (NF) channels, yet existing solutions are constrained by volatile operation, single-function limitations, and the inability to integrate NF and FF functionalities. Here, we present a nonvolatile reconfigurable terahertz metasurface platform leveraging the phase-change material GeSbTe(GST) to achieve on-demand dual-channel modulation-a first in the terahertz regime. By exploiting the stark conductivity contrast of GST between amorphous and crystalline states, our design enables energy-efficient switching between NF-SPP manipulation and FF-wavefront engineering without requiring continuous power input.
View Article and Find Full Text PDFBioinspir Biomim
September 2025
Mechanical Engineering, University of California Berkeley, 6177 Etcheverry Hall, Berkeley, California, 94720, UNITED STATES.
Riblets inspired by natural shark skin denticles are widely recognized for their drag-reducing performance. Although previous research has predominantly focused on two-dimensional riblet geometries, three-dimensional topographies remain underexplored due to the complex architecture of denticle-inspired surfaces. Natural riblet arrays, comprising thousands of interconnected denticles, pose challenges in terms of parameterization, simulation, and fabrication.
View Article and Find Full Text PDFMicromachines (Basel)
July 2025
Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.
Harbor seals () have excellent perception of water disturbances and can still sense targets as far as 180 m away, even when they lose their vision and hearing. This exceptional capability is attributed to the undulating structure of its vibrissae. These specialized whiskers not only effectively suppress vortex-induced vibrations (VIVs) during locomotion but also amplify the vortex street signals generated by the wake of a target, thereby enhancing the signal-to-noise ratio (SNR).
View Article and Find Full Text PDFEur Respir J
August 2025
Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
Background: Interest in bronchiectasis is increasing and no prior study has used Artificial Intelligence (AI) to interrogate its rich, multidimensional literature to characterize research trends, themes and knowledge gaps.
Methods: We reviewed original bronchiectasis research between 1949-2024 (75-year period) to identify, characterize and assess research trends and trajectories using two AI-powered approaches: (1) ATLAS, an AI-topic modelling tool and (2) a custom model, leveraging ChatGPT embedding and text-generation models.
Results: AI-powered analytics reveal a nine-fold increase in bronchiectasis research speed since 2000, typified by enhanced richness with four new research topics emerging every five years.
ACS Nano
September 2025
Department of Electronic Materials Engineering, Research School of Physics, Australian National University, Canberra ACT 2601, Australia.
Circular dichroism, arising from interactions with light fields of opposite spin angular momentum, has become a fundamental tool for molecular characterization. Meanwhile, helical dichroism (HD)─the dichroic response to vortex beams carrying opposite orbital angular momentum (OAM)─offers an alternative approach for probing chiral molecules and photonic structures. Previous demonstrations of HD have been limited to nonresonant light-matter interactions with chiral micro- and nanostructures, leaving the realization of resonant helical dichroism largely unexplored.
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