Waveguide-induced coalescence of exceptional points

Wang, Xingyuan; Wang, Fei-Fan; Hu, Xiaoyong

doi:10.1103/physreva.101.053820

Cited by 12 publications

(5 citation statements)

References 33 publications

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“…The exceptional point (EP) is one ubiquitous concept in non-Hermitian physics which was first proposed by Bender and Boettcher [15]. It has attracted a lot of research interest [16][17][18]. The EPs are non-Hermitian energy degeneracies at which the eigenvalues and corresponding eigenvectors simultaneously coalesce [19].…”

Section: Introductionmentioning

confidence: 99%

Extremely asymmetric absorption and reflection near the exceptional point for three-dimensional metamaterial

Wu,

Zhang,

et al. 2024

J. Phys. D: Appl. Phys.

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In recent years, particular physical phenomena enabled by non-Hermitian metamaterial systems have attracted significant research interests. In this paper, a non-Hermitian three-dimensional metamaterial near the exceptional point (EP) is proposed to demonstrate extremely asymmetric absorption and reflection. Unlike its conventional counterparts, this proposed metamaterial is constructed with a loss-assisted design. Localized losses are introduced into the structure by combining our technique of graphene-based resistive inks with conventional printed circuit board (PCB) process. Extremely asymmetric absorption and reflection near the EP are experimentally observed by tuning the loss between split ring resonators (SRRs) in the meta-atoms. Simultaneously, by linking the equivalent circuit model (ECM) with the Hamiltonian quantum physical model, the equivalent non-Hermitian Hamiltonian is obtained and a non-Hermitian transmission matrix is constructed. We show that tuning the structure and circuit parameters of the ECM produces a metamaterial system with EP response. Our system can be used in the design of asymmetric metamaterial absorbers. Our work lays down the way for the manipulation of EP to develop perfect absorption, sensing and other applications in the 3D metamaterial platform.

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Section: Introductionmentioning

confidence: 99%

Extremely asymmetric absorption and reflection near the exceptional point for three-dimensional metamaterial

Wu,

Zhang,

et al. 2024

J. Phys. D: Appl. Phys.

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“…It has been shown that higherorder EPs can exhibit greater advantages than EP2s in spontaneous emission enhancement [65], sensitive detection [69][70][71][72], topological characteristics [73][74][75]. With these superiorities, higher-order EPs are being intensively studied in various systems [76][77][78][79][80][81][82][83][84][85] but attract less attention in non-Hermitian COM systems. For this, how to construct higher-order EPs in non-Hermitian COM systems is strongly demanded.…”

Section: Introductionmentioning

confidence: 99%

Higher-order exceptional point in a blue-detuned non-Hermitian cavity optomechanical system

Xiong,

Li,

Zhang

et al. 2022

Preprint

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Higher-order exceptional points (EPs) in non-Hermitian systems have attracted great interest due to their advantages in sensitive enhancement and distinct topological features. However, realization of such EPs is still challenged because more fine-tuning parameters is generically required in quantum systems, compared to the second-order EP (EP2). Here, we propose a non-Hermition three-mode optomechanical system in the blue-sideband regime for predicting the third-order EP (EP3). By deriving the pseudo-Hermition condition for the proposed system, one cavity with loss and the other one with gain must be required. Then we show EP3 or EP2 can be observed when the mechanical resonator (MR) is neutral, loss or gain. For the neutral MR, we find both two degenerate or two non-degenerate EP3s can be predicted by tuning system parameters in the parameter space, while four non-degenerate EP2s can be observed when the system parameters derivate from EP3s, which is distinguished from the previous study in the red-detuned optomechanical system. For the gain (loss) MR, we find only two degenerate EP3s or EP2s can be predicted by tuning enhanced coupling strength. Our proposal provides a potential way to predict higher-order EPs or multiple EP2s and study multimode quantum squeezing around EPs using the blue-detuned non-Hermitian optomechanical systems.

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“…So far, higher-order EPs have been achieved in various systems including ring resonators [28], coupled-resonator optical waveguides [29], weakly deformed microdisks [30,31], electronic circuits [32], unidirectionally coupled photonic spin-orbit systems [33], supersymmetric arrays [34], non-Hermitian lattices [35], and ferromagnetic trilayers [36]. Additionally, a systematic methodology to achieve higher-order EPs in low-dimensional parameter space has been proposed [37][38][39], and higher-order EPs have been studied in terms of non-Hermitian skin effects as well [40].…”

Section: Introductionmentioning

confidence: 99%

Classification of multiple arbitrary-order non-Hermitian singularities

Ryu,

Han,

2021

Preprint

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We demonstrate general classifications of Riemann surface topology generated by multiple arbitrary-order exceptional points of quasi-stationary states. Our studies reveal all possible product permutations of holonomy matrices that describe a stroboscopic encircling of 2nd order exceptional points. The permutations turn out to be categorized into a finite number of classes according to the topological structures of the Riemann surfaces. We further show that the permutation classes can be derived from combinations of cyclic building blocks associated with higher-order exceptional points. Our results are verified by an effective non-Hermitian Hamiltonian founded on generic Jordan forms and then examined in physical systems of desymmetrized optical microcavities.

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Waveguide-induced coalescence of exceptional points

Cited by 12 publications

References 33 publications

Extremely asymmetric absorption and reflection near the exceptional point for three-dimensional metamaterial

Extremely asymmetric absorption and reflection near the exceptional point for three-dimensional metamaterial

Higher-order exceptional point in a blue-detuned non-Hermitian cavity optomechanical system

Classification of multiple arbitrary-order non-Hermitian singularities

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