PT Symmetry Induced Rings of Lasing Threshold Modes Embedded with Discrete Bound States in the Continuum

Song, Qianju; Dai, Shiwei; Han, Dezhuan; Zhang, Z. Q.; Chan, Che Ting; Zi, Jian

doi:10.1088/0256-307x/38/8/084203

Cited by 12 publications

(6 citation statements)

References 47 publications

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“…However, their dispersion carries important implications for system stability-an aspect often overlooked in theoretical studies of PT-symmetric systems. We note that a similar finding was previously reported in 1D periodic PT-symmetric systems, [66] where PT-symmetric perturbations create so-called PT-BIC rings, with similar implications for stability, [67] although the CPA-laser aspect was not discussed. The proposed theoretical framework reveals a fundamental connection between BICs and different scattering extrema and the topological nature of the emerging singularities.…”

Section: Bics and Topological S-matrix Singularitiessupporting

confidence: 84%

Non‐Hermitian Control of Topological Scattering Singularities Emerging from Bound States in the Continuum

Sakotic

Stanković

Bengin

et al. 2023

Laser & Photonics Reviews

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Leveraging topological properties in the response of electromagnetic systems can greatly enhance their potential. Although the investigation of singularity‐based electromagnetics and non‐Hermitian electronics has considerably increased in recent years in the context of various scattering anomalies, their topological properties have not been fully assessed. In this work, it is theoretically and experimentally demonstrated that non‐Hermitian perturbations around bound states in the continuum can lead to singularities of the scattering matrix, which are topologically nontrivial and comply with charge conservation. The associated scattering matrix poles, zeros, and pole‐zero pairs delineate extreme scattering events, including lasing, coherent perfect absorption, and absorber‐lasers. The presented framework enables a recipe for generation, annihilation, and addition of these singularities in electric circuits, with potential for extreme scattering engineering across a broad range of the electromagnetic spectrum for sensing, wireless power and information transfer, polarization control, and thermal emission devices.

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Section: Bics and Topological S-matrix Singularitiessupporting

confidence: 84%

Non‐Hermitian Control of Topological Scattering Singularities Emerging from Bound States in the Continuum

Sakotic

Stanković

Bengin

et al. 2023

Laser & Photonics Reviews

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“…Besides, there may be dissociative C-points far away from V-points in momentum space due to complex mode interactions even if the C 2 symmetry is maintained, as discussed by Ye et al [50] Up to now, most studies on momentum-space polarization fields are for photonic structures with time-reversal symmetry. In recent work, Song et al [55,56] studied theoretically polarization singularities in photonic systems with parity-time symmetry, revealing a new type of non-radiative V-points, i.e., pt-BICs which can be excited externally but can not radiate.…”

Section: Lifting the Degeneracy By Breakingmentioning

confidence: 99%

Momentum-space polarization fields in two-dimensional photonic-crystal slabs: Physics and applications

Liu¹,

Shi²,

Chan³

et al. 2022

Chinese Phys. B

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In addition to non-radiative guided modes, two-dimensional photonic-crystal slabs support guided resonant ones which can radiate into free space. From the polarization states of these guided resonances, a polarization field on a photonic band can be constructed in momentum space. Momentum-space polarization fields display complicated configurations and patterns with different types of polarization singularities inside, shedding new light on the manipulations of light flows. In this review, we summarize the recent research progress on momentum-space polarization fields and singularities in two-dimensional photonic-crystal slabs, focusing on their unique optical properties and potential applications as well.

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“…[4] The PT symmetry not only provides additional spatial modulation in optical systems, but also brings about new physical effects, such as negative refraction, [5] asymmetric invisibility, [6] and splitting of bound states in the continuum (BICs) into two states with purely real energy: PT-BICs and threshold states. [7] Zero-index metamaterial (ZIM) refers to material whose dielectric constant and magnetic permeability are both close to zero or one of them approaches to zero, i.e. epsilon-nearzero (ENZ) and magnetic permeability-near-zero (MNZ) materials.…”

Section: Introductionmentioning

confidence: 99%

Novel transmission property of zero-index metamaterial waveguide doped with gain and lossy defects

Zhu 朱,

Chai 柴,

Lu 路

2023

Chinese Phys. B

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Taking inspiration from quantum parity-time (PT) symmetries that have gained immense popularity in the emerging fields of non- Hermitian optics and photonics, the interest of exploring more generalized gain-loss interactions is never seen down. In this paper we theoretically present new fantastic properties through a zero-index metamaterial (ZIM) waveguide loaded gain and loss defects. For the case of epsilon-and-mu-near-zero (EMNZ) based ZIM medium, electromagnetic (EM) waves are cumulative and the system behaves as an amplifier when the loss cavity coefficient is greater than the gain cavity coefficient. Conversely, when loss is less than gain, EM waves are dissipated and the system behaves as an attenuator. Moreover, our investigation is extended to non-Hermitian scenarios characterized by tailored distributions of gain and loss in the epsilon-near-zero (ENZ) host medium. The transport effect in ZIM waveguide is amplified in one mode, while it is dissipative in the other mode, which breaks the common sense and its physic is analyzed by magnetic flux. That is which cavity has the smaller loss/gain coefficient, the larger its magnetic flux, which cavity dominates. This paper is of significant importance in the manipulation of electromagnetic waves and light amplification as well as the enhancement of matter interactions.

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PT Symmetry Induced Rings of Lasing Threshold Modes Embedded with Discrete Bound States in the Continuum

Cited by 12 publications

References 47 publications

Non‐Hermitian Control of Topological Scattering Singularities Emerging from Bound States in the Continuum

Non‐Hermitian Control of Topological Scattering Singularities Emerging from Bound States in the Continuum

Momentum-space polarization fields in two-dimensional photonic-crystal slabs: Physics and applications

Novel transmission property of zero-index metamaterial waveguide doped with gain and lossy defects

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