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Photonic crystal micro-ring resonators (PhC-MRRs) hold promise as compact, high-Q cavities, for a plethora of on-chip applications. However, the challenges of mode matching and resonance analysis in these devices pose significant design hurdles, compared with straightforward waveguide based MRRs. In this study, we propose an extended supercell containing both straight and bending structures that satisfy the periodicity requirements. This supercell structure, which is optimized to reduce corner reflections, features a lattice constant, a = 364 nm and filling factor, = 0.33. We extend the supercell to construct a hexagonal PhC-MRR with radius of 13a and 'bus-to-ring' coupling gap, g = 3a. The PhC-MRR structure with what we refer to as 'mirror optimized' corners exhibits a transmission spectrum with six, equally spaced, high-Q pure guided cavity resonances with a free spectral range (FSR) of 18 nm, across a broad bandwidth from 1500 nm to 1600 nm.
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http://dx.doi.org/10.1364/OE.564915 | DOI Listing |
Phys Rev Lett
August 2025
The University of Tokyo, Research Center for Advanced Science and Technology, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan.
Hopfions-higher-dimensional topological quasiparticles with sophisticated 3D knotted spin textures discovered in condensed matter and photonic systems-show promise in high-density data storage and transfer. Here, we present crystalline structures of hopfions lying in space-time constructed by spatiotemporally structured light. Practical methodologies using bichromatic structured light beams or dipole arrays to assemble 1D and higher dimensional hopfion lattices are proposed, and a technique for tailoring topological orders is elucidated.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Jilin University, State Key Laboratory of Integrated Optoelectronics, JLU Region, College of Electronic Science and Engineering, Changchun 130012, China.
Exceptional rings (ERs) are high-dimensional non-Hermitian topologies formed by exceptional points, significantly enriching the topological properties of non-Hermitian systems. Because of the intricate topology and symmetry requirements, the realization of ERs generally demands complex structures and precise parameter tuning, resulting in relatively few experimental observations in high-dimensional periodic systems. Here, we show that even the simplest 1D non-Hermitian periodic systems can support multiple ERs, enabled by the system's multiple degrees of freedom which naturally accommodate diverse non-Hermitian perturbations.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
Okayama University, Department of Physics, Okayama 700-8530, Japan.
The doped topological insulator Cu_{x}Bi_{2}Se_{3} has attracted considerable attention as a new platform for studying novel properties of spin-triplet and topological superconductivity. In this work, we performed synchrotron x-ray diffraction measurements on Cu_{x}Bi_{2}Se_{3} (0.24≤x≤0.
View Article and Find Full Text PDFPhys Rev Lett
August 2025
The Hong Kong University of Science and Technology, Department of Physics and Institute for Advanced Study, Clear Water Bay, Hong Kong SAR, China.
Photonic crystals are artificial materials characterized by a photonic band structure that governs the propagation of light waves. The photonic gap was originally introduced to inhibit spontaneous emission and facilitate photon localization. In this essay, I will highlight how, despite the established understanding of photonic crystals, they remain highly relevant today.
View Article and Find Full Text PDFACS Nano
September 2025
Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States.
Achieving high performance nanoscale photonic functionalities remains extraordinarily challenging when using naturally derived biomaterials. The ability to manipulate ultrathin films of structural proteins─combined with photolithographic control of their polymorphism─unlocks a compelling route toward engineering biopolymer-based photonic crystals with precisely defined photonic bandgaps and reconfigurable structural colors. In this work, we describe a robust, water-based fabrication process for silk/inorganic hybrid one-dimensional (1D) photonic crystals that overcomes many of the conventional difficulties in ensuring reproducibility, uniformity, and reliability at the nanoscale.
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