Exceptional points (EPs), at which more than one eigenvalue and eigenvector coalesce, are unique spectral features of non-Hermiticity (NH) systems. They exist widely in open systems with complex energy spectra. We experimentally demonstrate the appearance of paired EPs in a periodical-driven degenerate optical cavity along the synthetic orbital angular momentum dimension with a tunable parameter. The complex-energy band structures and the key features of EPs, i.e., their bulk Fermi arcs, parity-time symmetry breaking transition, energy swapping, and half-integer band windings, are directly observed by detecting the wavefront angle-resolved transmission spectrum. Our results demonstrate the flexibility of using the photonic synthetic dimensions to implement NH systems beyond their geometric dimension and EP-based sensing.
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http://dx.doi.org/10.1126/sciadv.abp8943 | DOI Listing |
Sci Adv
January 2025
State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou 310027, China.
Solution-processed semiconductor lasers are next-generation light sources for large-scale, bio-compatible and integrated photonics. However, overcoming their performance-cost trade-off to rival III-V laser functionalities is a long-standing challenge. Here, we demonstrate room-temperature continuous-wave perovskite polariton lasers exhibiting remarkably low thresholds of ~0.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, 19716, USA.
Exceptional points (EPs) have been extensively explored in mechanical, acoustic, plasmonic, and photonic systems. However, little is known about the role of EPs in tailoring the dynamic tunability of optical devices. A specific type of EPs known as chiral EPs has recently attracted much attention for controlling the flow of light and for building sensors with better responsivity.
View Article and Find Full Text PDFAnal Chim Acta
January 2025
MOE Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, 350116, PR China. Electronic address:
Flap endonuclease 1 (FEN1) plays a vital role in cancer by modulating DNA repair mechanisms, inducing genomic instability, and serving as a promising biomarker for cancer diagnosis and prognosis. In this work, we present the development of a novel DNAzyme signal amplification-directed point-of-care sensing system (Dz-PGM) for the sensitive and specific detection of FEN1. The Dz-PGM system utilizes DNAzyme signal amplification in conjunction with a personal glucose meter (PGM) for reporting, capitalizing on a biochemical cascade initiated by FEN1 recognition.
View Article and Find Full Text PDFNature
January 2025
Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.
The concept of non-Hermiticity has expanded the understanding of band topology, leading to the emergence of counter-intuitive phenomena. An example is the non-Hermitian skin effect (NHSE), which involves the concentration of eigenstates at the boundary. However, despite the potential insights that can be gained from high-dimensional non-Hermitian quantum systems in areas such as curved space, high-order topological phases and black holes, the realization of this effect in high dimensions remains unexplored.
View Article and Find Full Text PDFSci Adv
January 2025
Institute of Physics, University of Rostock, Rostock, Germany.
Exceptional points facilitate peculiar dynamics in non-Hermitian systems. Yet, in photonics, they have mainly been studied in the classical realm. In this work, we reveal the behavior of two-photon quantum states in non-Hermitian systems across the exceptional point.
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