scholarly journals Bound states in the continuum in periodic structures with structural disorder

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ekaterina E. Maslova ◽  
Mikhail V. Rybin ◽  
Andrey A. Bogdanov ◽  
Zarina F. Sadrieva

Abstract We study the effect of structural disorder on the transition from the bound states in the continuum (BICs) to quasi-BICs by the example of the periodic photonic structure composed of two layers of parallel dielectric rods. We uncover the specificity in the robustness of the symmetry-protected and accidental BICs against various types of structural disorder. We analyze how the spatial mode localization induced by the structural disorder results in an effective reduction of the system length and limits the Q factor of quasi-BICs. Our results are essential for the practical implementation of BICs especially in natural and self-assembled photonic structures, where the structural disorder plays a crucial role.

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Chan Kyaw ◽  
Riad Yahiaoui ◽  
Joshua A. Burrow ◽  
Viet Tran ◽  
Kyron Keelen ◽  
...  

AbstractBound states in the continuum (BICs) are widely studied for their ability to confine light, produce sharp resonances for sensing applications and serve as avenues for lasing action with topological characteristics. Primarily, the formation of BICs in periodic photonic band gap structures are driven by symmetry incompatibility; structural manipulation or variation of incidence angle from incoming light. In this work, we report two modalities for driving the formation of BICs in terahertz metasurfaces. At normal incidence, we experimentally confirm polarization driven symmetry-protected BICs by the variation of the linear polarization state of light. In addition, we demonstrate through strong coupling of two radiative modes the formation of capacitively-driven Freidrich-Wintgen BICs, exotic modes which occur in off-Γ points not accessible by symmetry-protected BICs. The capacitance-mediated strong coupling at 0° polarization is verified to have a normalized coupling strength ratio of 4.17% obtained by the Jaynes-Cummings model. Furthermore, when the polarization angle is varied from 0° to 90° (0° ≤ ϕ < 90°), the Freidrich-Wintgen BIC is modulated until it is completely switched off at 90°.


2021 ◽  
Author(s):  
Tian Sang ◽  
Qing Mi ◽  
Yao Pei ◽  
Chaoyu Yang ◽  
Shi Li ◽  
...  

Abstract In photonics, it is essential to achieve high quality (Q)-factor resonances to enhance light-mater interactions for improving performances of optical devices. Herein, we demonstrate that high Q-factor dual-band Fano resonances can be achieved by using a planar nanohole slab (PNS) based on the excitation of bound states in the continuum (BICs). By shrinking or expanding the tetramerized holes of the superlattice of the PNS, symmetry-protected BICs can be excited and the locations of Fano resonances as well as their Q-factors can be flexibly tuned. Physical mechanisms for the dual-band Fano resonances can be interpreted as the resonant couplings between the electric-toroidal dipoles or the magnetic-toroidal dipoles based on the far-field multiple decompositions and the near-field distributions of the superlattice. The dual-band Fano resonances of the PNS possess polarization independent feature, they can be survived even the geometric parameters of the PNS are significantly altered, making them more suitable for potential applications.


2019 ◽  
Vol 100 (6) ◽  
Author(s):  
Shiyu Li ◽  
Chaobiao Zhou ◽  
Tingting Liu ◽  
Shuyuan Xiao

2021 ◽  
Vol 130 (23) ◽  
pp. 233102
Author(s):  
Lei Wang ◽  
Zhenyu Zhao ◽  
Mingjie Du ◽  
Hua Qin ◽  
Rajour Tanyi Ako ◽  
...  

2019 ◽  
Vol 115 (14) ◽  
pp. 141103 ◽  
Author(s):  
Nicholas Karl ◽  
Polina P. Vabishchevich ◽  
Sheng Liu ◽  
Michael B. Sinclair ◽  
Gordon A. Keeler ◽  
...  

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