arXiv subjects

Xusheng Xia

Publications and source records attributed to Xusheng Xia.

3 recordsLinked to original sources

arXiv2026

Spatiotemporal Optical Vortices From All-Dielectric Bilayer Metagratings

Spatiotemporal optical vortices (STOVs) carry transverse orbital angular momentum within the space-time domain, rendering them powerful tools for constructing high-dimensional and quantum optical fields. However, most existing approaches rely on highly lossy metallic structures or complex pulse-shaping systems. Here, we propose an all-dielectric route to STOV generation based on symmetry-protected bound states in the continuum (BICs) in a bilayer metagrating and provide proof-of-concept validation of its key momentum-frequency signatures. By simply introducing a lateral shift between the upper and lower layers of the vertical slots on the dielectric metagrating, the Γ-point BIC transforms into a quasi-BIC (qBIC) with momentum-dependent directional radiation and asymmetric coupling. This qBIC further leads to an isolated zero-transmission dip associated with a clear phase singularity and branch cut in the momentum-frequency response, enabling stable STOV generation under excitation by a spatiotemporal Gaussian pulse. The multipole analysis of the qBIC reveals the key role of the Kerker-type interference between its electric and magnetic dipoles and associated asymmetric coupling in the STOV generation. Experimentally, free-space transmission measurements reveal a transmission zero and a branch cut that agree excellently with theoretical analysis. Therefore, our work provides an experimentally validated, scalable route for manipulating spatiotemporal optical fields on low-loss all-dielectric metasurfaces via only gliding offsets, with potential applications in directional coupling of quantum light sources and spatiotemporal shaping of single-photon wave packets.

physics.optics↗

arXiv2026

Open dataset for benchmarking scaling laws of high-energy laser atmospheric propagation

Scaling laws are increasingly used as fast surrogate models for high energy laser atmospheric propagation, yet their calibration and comparison still depend on large collections of high-fidelity wave-optics simulations. Existing studies usually rely on privately organized simulation outputs, which makes it difficult to reproduce published fits or evaluate new surrogate formulations on a shared benchmark. We present a public simulation dataset for high energy laser atmospheric propagation with coupled turbulence and thermal blooming. The release contains 226,500 cases spanning target speed, emission geometry, aperture diameter, visibility, aerosol model, beam quality, turbulence strength, and laser power. Data are organized as a case-level main table linked to indexed long-exposure irradiance arrays and centralized metadata, which supports statistical analysis without hiding the underlying field outputs. The simulation pipeline is based on split-step wave-optics propagation with turbulence, attenuation, and thermal-blooming models that have been validated against established propagation references. The dataset is intended for scaling-law calibration, benchmark comparison, surrogate-model training, sensitivity analysis, and inverse studies.

physics.optics↗

arXiv2025

Kirigami-based Flexible Metasurface with Reconfigurable Intrinsic Chirality from Zero to Near-unity

Chiral responses in electromagnetic metasurfaces are typically categorized as extrinsic, resulting from asymmetric interactions between the structure and incident waves, and intrinsic, arising from three-dimensional symmetry breaking of the unit cell. However, most existing metasurface designs target only one type of chirality and lack a unified, continuously tunable platform for broader chiroptical control. To address this limitation, the designed kirigami-based flexible metasurface is proposed for dynamic, continuous modulation of chirality, which expands the control scope to both extrinsic and intrinsic chiral responses within a single, reconfigurable platform. Initially, the unfolded metasurface exhibits extrinsic chirality under oblique incidence. By introducing well-designed kirigami-based cuts and folds, the metasurface transitions from a planar and achiral configuration to a three-dimensional chiral geometry that breaks the mirror symmetry, thereby exhibiting tunable intrinsic chirality and asymmetric extrinsic chirality. As the folding angle increases, the resulting deformation enables continuous tuning of the chiral response, with circular dichroism and its asymmetry under oblique incidences progressively increasing and reaching pronounced levels across the X-band. Our work provides a lightweight, easy-fabricated, and mechanically reconfigurable metasurface, which offers strong potential for future development in adaptive photonic systems and advanced chiroptical technologies.

physics.optics↗