Ming Fang

The co‐manipulation of orbital angular momentum (OAM) in real and momentum spaces presents challenges in electromagnetic wave engineering, primarily due to the counteraction between topological defects and disorder, particularly in overcoming the intrinsic bandwidth limitations of topological photonic systems. Recent advancements have shown the generation of real‐momentum space vortices through bound states in the continuum in topological photonic crystals (PhCs), but these implementations face critical trade‐offs between spatial disorder tolerance and operating bandwidth. Here, we present a disorder‐empowered metasurface architecture that breaks this paradigm through geometric‐phase engineering combined with topological PhC design. Our platform achieves simultaneous broadband OAM generation in both real and momentum spaces, notably demonstrating a 40% fractional bandwidth in the momentum domain—far surpassing previous records. Experimental results break the prevailing notion that real‐space disorder inevitably degrades momentum‐space performance, demonstrating instead that engineered disorder actively stabilizes dual‐space broadband characteristics over an ultra‐wide frequency range. This phenomenon originates from geometrically locked Pancharatnam‐Berry phase robustness and self‐compensated momentum‐space topology, enabling wavelength‐independent vortex generation with preserved charge orthogonality across domains. This dual‐broadband capability expands the information‐carrying potential of topological photonic devices, paving the way for high‐capacity communication systems that leverage disorder as a beneficial design feature rather than a limiting factor.

A parallel finite-difference time-domain (FDTD) architecture that fundamentally overcomes the computational bottlenecks of traditional implicit solvers through two engineering combinations is presented. First, we construct a distributed multi-core computing framework that integrates fast Fourier transform (FFT) techniques to enable parallel processing of the discrete cosine/sine transform (DCT/DST) operations required for spatial filtering. Followed by an explicit FDTD stability methodology that eliminates the matrix inversion bottleneck inherent to conventional implicit unconditionally stable FDTD approaches. Numerical experiments reveal speedup of 3.4 times compared to traditional CPU-based parallel FDTD implementations. The proposed architecture establishes a new paradigm for extreme-scale electromagnetic simulations by integrating spatially filtering with parallelization techniques.

Achieving ultra-low reflection across the visible spectrum and under wide incident angles is of considerable importance for broadband antireflection coatings and optical interface engineering. Here, we introduce a bilayer subwavelength dielectric metamaterial together with a rapid and generalizable inverse-design framework based on a tandem residual deep neural network architecture. The metamaterial is fabricated entirely from the same dielectric material as the substrate, ensuring excellent compatibility and straightforward integration. Owing to its all-dielectric composition, the design principle can also be readily extended to other spectral bands as required. Furthermore, the framework can directly incorporate different substrate material parameters and output the corresponding optimized geometry, demonstrating strong adaptability and scalability. The inverse-design strategy integrates a forward network (FNet) and an inverse network (INet), both constructed using lightweight residual blocks to ensure solution uniqueness and high prediction fidelity. Simulations show that the optimized bilayer metamaterial achieves a maximum reflectivity of less than 3% throughout the visible band (400–700 nm) and maintains stable ultra-low-reflection performance for incident angles up to 80°. Beyond providing a compact and fabrication-friendly route to broadband wide-angle antireflection, this work establishes a fast, accurate, and broadly applicable inverse-design paradigm for next-generation nanophotonic structures.

Long‐wave infrared (LWIR) metalenses, capable of precise wavefront modulation through subwavelength meta‐atoms, represent a transformative advancement in infrared optics, offering a compact alternative to conventional refractive elements. This work systematically examines the fundamental principles, typical designs, and fabrication challenges of LWIR metalenses, with an emphasis on different phase modulation strategies, presenting their distinct advantages and limitations. Recent breakthroughs in aberration correction, wide‐field imaging, and polarization‐sensitive functionalities are critically reviewed, alongside computational optimization approaches such as deep learning and topology algorithms. Fabrication techniques, including advanced lithography and etching, are evaluated for their scalability and precision in realizing high‐performance metasurfaces. Persistent challenges in efficiency, thermal stability, and large‐scale manufacturing underscore the need for novel materials, refined nanofabrication methods, and integrated design frameworks. By addressing these barriers, LWIR metalenses hold potential to revolutionize applications in thermal imaging, defense systems, and biomedical sensing, paving the way for next‐generation infrared technologies.

This study introduces a laser cavity structure that has been designed utilizing the principles of Bloch surface feature states and a laser cavity with an exceptionally high Q-factor has been successfully realized. The interaction with the surrounding free space induces the leakage of surface modes; nevertheless, the leakage in the forward and back-reflected directions can undergo destructive interference, resulting in the emergence of a perfectly confined surface state with zero leakage. To comprehensively appraise the performance and characteristics of this structure, a four-level system model has been established. The laser cavity structure, which is based on Bloch surface feature states, exhibits considerable potential for practical applications. It can be effectively employed to enhance the performance and efficiency of lasers, thereby catering to the evolving demands of the optoelectronics field in the future.

Conventional dielectric waveguides confine electromagnetic waves through refractive index contrast between core and cladding materials, yet inherently lack nonreciprocal transmission capabilities. In this study, we demonstrate a waveguide system engineered via artificial gauge fields that achieves simultaneous optical confinement and nonreciprocal propagation without requiring additional cladding structures, thereby substantially reducing system complexity. Theoretical analysis and experimental verification reveal that directly tilted structures effectively generate gauge fields to modify dispersion relations, thereby eliminating backward propagation channels and ensuring robust unidirectional wave propagation. Our experimental results closely align with the physical model predictions, validating the accuracy of our methodology. Compared with traditional dielectric waveguides, the structural simplicity of our design significantly reduces fabrication complexity, making it particularly suitable for integrated photonic circuits and advanced optical systems. This research establishes an effective strategy for realizing unidirectional wave propagation, thus providing a novel paradigm for developing next-generation photonic devices.