Normal incidence filters using symmetry-protected modes in dielectric subwavelength gratings

Xuan, Chuang; Tian, Hao; Du, Yan; Shi, Guang; Zhou, Zhongxiang

doi:10.1038/srep36066

Cited by 67 publications

(45 citation statements)

References 28 publications

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“…In particular, the studies on BICs are motivated by applications to resonant light enhancement [11][12][13] and lasing 14,15 . Another remarkable property of BICs is the emergence of a collapsing Fano feature in its parametric vicinity [16][17][18][19] , that can be potentially employed to narrow-band filters 20,21 . To the best of our knowledge, optical resonances with infinite lifetime in the Γ-point (i.e.…”

Section: Introductionmentioning

confidence: 99%

Optical defect mode with tunableQfactor in a one-dimensional anisotropic photonic crystal

2018

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We consider a one-dimensional photonic crystal composed of alternating layers of isotropic and anisotropic dielectric materials. Such a system has different band structures for different polarizations of light. We demonstrate that if an anisotropic defect layer is inserted into the structure, the crystal can support an optical bound state in the continuum. By tilting the principle dielectric axes of the defect layer relative to those of the photonic crystal we observe a long-lived resonance in the transmission spectrum. We derive an analytical expression for the decay rate of the resonance that agrees well with the numerical data by the Berreman anisotropic transfer matrix approach. An experimental set-up with a liquid crystal defect layer is proposed to tune the Q-factor of the resonance through applying an external electric field. We speculate that the set-up provides a simple and robust platform for observing optical bound states in the continuum in the form of resonances with tunable Q-factor.

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Section: Introductionmentioning

confidence: 99%

Optical defect mode with tunableQfactor in a one-dimensional anisotropic photonic crystal

2018

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“…In fact the collapse of a Fano resonance is a generic feature inherent to BSCs [56][57][58][59] including quasi-BSCs in plasmonics [60]. In the field of optics the above feature has allowed for design of narrow band normal incidence filters [61][62][63]. The BSCs in linear arrays of dielectric spheres were first reported in [64].…”

Section: Introductionmentioning

confidence: 99%

Light enhancement by quasi-bound states in the continuum in dielectric arrays

Bulgakov¹,

Максимов²

2017

Opt. Express

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The article reports on light enhancement by structural resonances in linear periodic arrays of identical dielectric elements. As the basic elements both subwavelength spheres and rods with circular cross section have been considered. In either case it has been demonstrated numerically that high-Q structural resonant modes originated from bound states in the continuum enable near-field amplitude enhancement by factor of 10-25 in the red-to-near infrared range in lossy silicon. The asymptotic behavior of the Q-factor with the number of elements in the array is explained theoretically by analyzing quasi-bound states propagation bands.

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“…This implies that resonant modes with arbi- * Corresponding author: mayylu@cityu.edu.hk trarily high Q-factors can be created by modifying the structure [40] or varying a physical parameter such as a component of the Bloch wavevector [41,42]. Applications of optical BICs include lasing [43], sensing [45], filtering [46,47], switching [48], nonlinear optics [41,49], etc. They are mostly related to the high-Q resonances, and are based on local fields enhanced by the resonances [50,51], or special features in scattering, transmission or other spectra [52,53].…”

Section: Introductionmentioning

confidence: 99%

Bound states with complex frequencies near the continuum on lossy periodic structures

Zhen

Yuan

2020

Phys. Rev. A

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On a lossless periodic dielectric structure sandwiched between two homogeneous media, bound states in the continuum (BICs) with real frequencies and real Bloch wavevectors may exist, and they decay exponentially in the surrounding homogeneous media and do not couple with propagating plane waves with the same frequencies and wavevectors. The BICs are of significant current interest, because they give rise to high-Q resonances when the structure or the Bloch wavevector is slightly perturbed. In this paper, the effect of a small material loss on the BICs is analyzed by a perturbation method and illustrated by numerical results. It is shown that bound states with complex frequencies near the continuum appear, but they behave differently depending on whether the BIC is symmetryprotected or not. The Bloch wavevector of a bound state with a complex frequency can be real if the original BIC is symmetry-protected, and it is usually complex if the original BIC is not symmetryprotected. Our study improves the theoretical understanding on BICs and provides useful insight for their practical applications.

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Normal incidence filters using symmetry-protected modes in dielectric subwavelength gratings

Cited by 67 publications

References 28 publications

Optical defect mode with tunableQfactor in a one-dimensional anisotropic photonic crystal

Optical defect mode with tunableQfactor in a one-dimensional anisotropic photonic crystal

Light enhancement by quasi-bound states in the continuum in dielectric arrays

Bound states with complex frequencies near the continuum on lossy periodic structures

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