Mutual coupling of corner-localized quasi-BICs in high-order topological PhCs and sensing applications

Chao, Minghao; Liu, Qingsong; Zhang, Wenjing; Zhuang, Lingyun; Song, Guofeng

doi:10.1364/oe.457274

Cited by 8 publications

(4 citation statements)

References 57 publications

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“…The sensitivity of the designed all-dielectric metasurface was higher than that of the metasurfaces in the cited references [43,[60][61][62][63][64]. Notably, only two other metasurfaces using a dielectric hybrid disk [65] and an Si crescentshaped nanoparticle as the unit cells exhibited higher sensitivity than the proposed designed metasurface. However, the dielectric hybrid disk metasurface operates in the near-infrared range, with the dielectric hybrid disks embedded in the air background, lacking a solid substrate and making physical realization challenging.…”

Section: Comparison Of Sensitivity With the Previous Study On Metasur...mentioning

confidence: 75%

Optimization of the Geometrical Design for an All-Dielectric Metasurface Sensor with a High Refractive-Index Response

Chang,

Yang,

Chen

et al. 2023

Chemosensors

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This study aims to develop a refractive-index sensor operating in the visible region using an all-dielectric metasurface, which was chosen for its advantages of low optical loss and narrow spectral bandwidth, compared to those of conventional metallic metasurfaces. COMSOL software was utilized as a calculation tool to simulate the resonant properties of an all-dielectric metasurface composed of a circular nanohole-structured titanium oxide (TiO2) thin film, with the aim of enhancing the sensitivity of the refractive index for sensing targets. The simulation focused on finding the best geometrical conditions for the all-dielectric metasurface to achieve high sensitivity. Two resonance modes observed in this metasurface were considered: the quasi-bound-state-in-the-continuum (qBIC) mode and the perfect-reflection (PR) mode. The simulated results demonstrated that high sensitivities of 257 nm/RIU at the PR mode and 94 nm/RIU at the qBIC mode in the visible spectral range could be obtained by periodically constructing the metasurface with a unit cell having a lattice constant of 350 nm, a nanohole radius of 160 nm, and a nanohole depth of 250 nm. Furthermore, the study showed that the resonance mode that enabled high sensitivity was the PR mode, with a sensitivity nearly three times larger than that of the qBIC mode and the ability to reach the highest reflectance at the resonance wavelength. The optimized feature had the highest reflectance at a resonant wavelength of 570.19 nm, and although the quality factor was 25.50, these designed parameters were considered sufficient for developing a refractive index biosensor with high sensitivity and optical efficiency when operating in the visible spectral range.

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Section: Comparison Of Sensitivity With the Previous Study On Metasur...mentioning

confidence: 75%

Optimization of the Geometrical Design for an All-Dielectric Metasurface Sensor with a High Refractive-Index Response

Chang,

Yang,

Chen

et al. 2023

Chemosensors

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show abstract

“…All-dielectric structures that support BICs have been widely used in the design of high- Q biosensors based on their advantages of low loss and high functionality. In this section, some all-dielectric BICs biosensors are introduced, including BICs gratings [ 57 , 58 , 59 , 60 , 61 , 62 , 63 ], symmetry-broken [ 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ] and topological-boundary-states-governed [ 78 ] BICs metasurfaces, and BICs PhCSs [ 56 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 ].…”

Section: Label-free Bics Optical Biosensors Based On Different Materi...mentioning

confidence: 99%

Label-Free Bound-States-in-the-Continuum Biosensors

et al. 2022

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Bound states in the continuum (BICs) have attracted considerable attentions for biological and chemical sensing due to their infinite quality (Q)-factors in theory. Such high-Q devices with enhanced light-matter interaction ability are very sensitive to the local refractive index changes, opening a new horizon for advanced biosensing. In this review, we focus on the latest developments of label-free optical biosensors governed by BICs. These BICs biosensors are summarized from the perspective of constituent materials (i.e., dielectric, metal, and hybrid) and structures (i.e., grating, metasurfaces, and photonic crystals). Finally, the current challenges are discussed and an outlook is also presented for BICs inspired biosensors.

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“…In addition to the characteristics of strong field localization and small mode volume, 0D corner states also show excellent robustness against fabrication flaws [16][17][18]. On this basis, they have enormous application value in the topological cavity [18,19], lasing [20,21], non-linear optics [22,23], and sensing [24]. However, for photonic crystals (PCs), the two kinds of polarization, transverse magnetic (TM) and transverse electric (TE) modes, are usually studied in a separate way.…”

Section: Introductionmentioning

confidence: 99%

Polarization-independent second-order photonic topological corner states

Lei¹,

Xiao²,

Liu³

et al. 2023

Preprint

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Recently, much attention has been paid to second-order photonic topological insulators (SPTIs), because of their support for highly localized corner states with excellent robustness. SPTIs have been implemented in either transverse magnetic (TM) or transverse electric (TE) polarizations in two-dimensional (2D) photonic crystals (PCs), and the resultant topological corner states are polarization-dependent, which limits their application in polarization-independent optics. However, to achieve polarization-independent corner states is not easy, since they are usually in-gap and the exact location in the topological bandgap is not known in advance. Here, we report on a SPTI based on a 2D square-lattice PC made of an elliptic metamaterial, and whether the bandgap is topological or trivial depends on the choice of the unit cell. It is found that locations of topological bandgaps of TM and TE polarizations in the frequency spectrum can be independently controlled by the out-of-plane permittivity ε ⊥ and in-plane permittivity ε ∥ , respectively, and more importantly, the location of in-gap corner states can also be separately manipulated by them. From this, we achieve topological corner states for both TM and TE polarizations with the same frequency in the PC by adjusting ε ⊥ and ε ∥ , and their robustness against disorders and defects are numerically demonstrated. The proposed SPTI provides a potential application scenario for polarization-independent topological photonic devices.

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Mutual coupling of corner-localized quasi-BICs in high-order topological PhCs and sensing applications

Cited by 8 publications

References 57 publications

Optimization of the Geometrical Design for an All-Dielectric Metasurface Sensor with a High Refractive-Index Response

Optimization of the Geometrical Design for an All-Dielectric Metasurface Sensor with a High Refractive-Index Response

Label-Free Bound-States-in-the-Continuum Biosensors

Polarization-independent second-order photonic topological corner states

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