Modifying the Quality Factors of the Bound States in the Continuum in a Dielectric Metasurface by Mode Coupling

• DOI: 10.1021/acsphotonics.2c01461
• Publication Date: 2022-12-23T20:44:35Z
• Authors: Zhaotang Li; Lidan Zhou; Zhuojun Liu; Mingcheng Panmai; Shulei Li; Jin Liu; Sheng Lan
• Keywords: Fano resonance

As optical resonances with high-quality (Q) factors, bound states in the continuum (BICs) supported a metamaterial low loss have attracted great interest due to their potential applications photonic devices different functionalities. However, most studies focus on influence of symmetry breaking constituent elements Q factors quasi-BICs, and less attention is paid coupling between elements. Here, we investigate numerically experimentally quasi-BICs revealed metasurfaces composed regularly arranged silicon (Si) nanoparticles without geometric symmetry. It found that appear transmission spectra as Fano lineshapes asymmetry parameters, depending strongly relative locations two modes involved interference. Apart from symmetry-protected BICs dominated by radiate only direction parallel metasurface, accidental at-Γ formed destructive interference are also revealed. The leakage light incidence originates such other existing same spectral range, which limits maximum quasi-BICs. Consequently, high-Q (1010 1013) observed Si (or breaking). More interestingly, metasurface exhibit strong dependence period metasurface. An exponential decrease factor when deviates value at achieved, implying crucial role mode determining factor. result, quasi-BIC may not exponentially nanoparticle increased. In comparison, sensitive By deliberately choosing period, achieved close those realized breaking. Our findings important for understanding physical origin so-called helpful designing based