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We show that an arbitrary body or aggregate can be made perfectly absorbing at discrete frequencies if a precise amount of dissipation is added under specific conditions of coherent monochromatic illumination. This effect arises from the…

Optics · Physics 2010-08-03 Y. D. Chong , Li Ge , Hui Cao , A. D. Stone

Coherent perfect tunneling in the presence of loss and asymmetry remains a fundamental challenge in wave transport, a universal problem across optics, acoustics, and quantum mechanics. Here we demonstrate coherent perfect tunneling at an…

Optics · Physics 2026-02-13 Huayang Cai , Bishuang Chen

Recent studies on non-Hermitian optical systems having exceptional points (EPs) have revealed a host of unique characteristics associated with these singularities, including unidirectional invisibility, chiral mode switching and laser…

Non-Hermitian degeneracies, also known as exceptional points (EPs), have been the focus of much attention due to their singular eigenvalue surface structure. Nevertheless, as pertaining to a non-Hermitian metasurface platform, the reduction…

We analyze the behavior of a non-Hermitian opened one-dimensional quantum system with $\mathcal{PT}$ symmetry. This system is built by a dimer, with balanced gains and losses described by a parameter $\gamma$. By varying $\gamma$ the system…

Quantum Physics · Physics 2024-04-11 J. Colín-Gálvez , E. Castaño , G. Báez , V. Domínguez-Rocha

In this study, we propose the application of non-Hermitian photonic crystals (PCs) with anisotropic emissions. Unlike a ring of exceptional points (EPs) in isotropic non-Hermitian PCs, the EPs of anisotropic non-Hermitian PCs appear as…

Optics · Physics 2023-03-29 Zhifeng Li , Hai Lin , Rongxin Tang , Haitao Chen , Jiaru Tang , Rui Zhou , Jing Jin , Y. Liu

Absorption of electromagnetic energy by a material is a phenomenon that underlies many applied problems, including molecular sensing, photocurrent generation and photodetection. Commonly, the incident energy is delivered to the system…

Optics · Physics 2018-06-11 Denis G. Baranov , Alex Krasnok , Timur Shegai , Andrea Alù , Y. D. Chong

A non-Hermitian system at an exceptional point (EP), a specific critical point (CP) associated with the parity-time symmetric phase transition, exhibits a sublinear response to perturbation and promise unprecedented sensitivity beyond the…

We show that gyrotropic structures with balanced gain and loss that respect anti-linear symmetries exhibit a giant non-reciprocity at the so-called exact phase where the eigenfrequencies of the isolated non-Hermitian set-up are real. The…

Classical Physics · Physics 2017-01-17 Roney Thomas , Huanan Li , F. M. Ellis , Tsampikos Kottos

The heightened sensitivity observed in non-Hermitian systems at exceptional points (EPs) has garnered significant attention. Typical EP sensor implementations rely on precise measurements of spectra and importantly, for real time sensing…

Optics · Physics 2023-10-18 Parul Sharma , Brijesh Kumar , Nihar Ranjan Sahoo , Anshuman Kumar

We report on experiments of perfect absorption for surface gravity waves impinging a wall structured by a subwavelength resonator. By tuning the geometry of the resonator, a balance is achieved between the radiation damping and the…

Fluid Dynamics · Physics 2019-01-30 Eduardo Monsalve , Agnes Maurel , Philippe Petitjeans , Vincent Pagneux

Systems operating at exceptional points (EPs) are highly responsive to small perturbations, making them suitable for sensing applications. Although this feature impedes the system working exactly at an EP due to imperfections arising during…

Optics · Physics 2024-01-19 Shahab Ramezanpour

Certain real parameters of a Hamiltonian, when continued to complex values, can give rise to singular points called exceptional points ($EP$'s), where two or more eigenvalues coincide and the complexified Hamiltonian becomes…

Mesoscale and Nanoscale Physics · Physics 2021-05-20 Ipsita Mandal

Exceptional points (EPs), at which both eigenvalues and eigenvectors coalesce, are ubiquitous and unique features of non-Hermitian systems. Second-order EPs are by far the most studied due to their abundance, requiring only the tuning of…

Optics · Physics 2023-01-02 Ipsita Mandal , Emil J. Bergholtz

The unique properties of exceptional point (EP) singularities, arising from non-Hermitian physics, have unlocked new possibilities for manipulating light-matter interactions. A tailored gain-loss variation, while encircling higher-order EPs…

Abstract An exceptional point of degeneracy (EPD) is induced in a system made of an electron beam interacting with an electromagnetic (EM) guided mode. This enables a degenerate synchronous regime in backward wave oscillators (BWOs) where…

Applied Physics · Physics 2021-06-16 Tarek Mealy , Ahmed F. Abdelshafy , Filippo Capolino

Exceptional points (EPs) in non-Hermitian systems offer a remarkably strong response to weak perturbations, but the nonorthogonal nature of the corresponding eigenvectors causes noise to diverge, hindering EPs practical application. Here,…

When two resonant modes in a system with gain or loss coalesce in both their resonance position and their width, a so-called "Exceptional Point" occurs which acts as a source of non-trivial physics in a diverse range of systems. Lasers…

Periodically time-varying media, known as photonic time crystals (PTCs), provide a promising platform for observing unconventional wave phenomena. We analyze the scattering of electromagnetic waves from spatially finite PTCs using the…

The interplay between coherent and dissipative dynamics required in various control protocols of quantum technology has motivated studies of open-system degeneracies, referred to as exceptional points (EPs). Here, we introduce a scheme for…

Quantum Physics · Physics 2023-08-23 Wallace S. Teixeira , Vasilii Vadimov , Timm Mörstedt , Suman Kundu , Mikko Möttönen