生物传感器环形偶极子共振超表面的仿真设计

Simulation design of toroidal dipole resonance-based metasurface for biosensor

目的:设计一种基于环形偶极子共振的石墨烯超表面,以提高生物传感器的检测灵敏度。方法:根据石墨烯超表面的工作频段和环形偶极子产生原理对超表面的结构和尺寸进行设计,并利用有限元仿真软件进行超表面建模。分析超表面在工作频段的透射谱线以及其在谐振频率处的表面电场与表面电流分布;将折射率可变的生物薄膜涂覆在超表面上模拟微生物样品,计算生物薄膜单位折射率变化引起的透射谱频移,继而推导出超表面的检测灵敏度。结果:设计的超表面能够成功激发环形偶极子共振。仿真计算结果表明,超表面在共振处的灵敏度约为42 GHz/RIU。结论:设计的超表面具有较高的品质因子,可提高检测灵敏度,该研究为基于环形偶极子共振的图案化石墨烯生物传感器的设计与优化提供了依据。

Objective To design a graphene metasurface based on toroidal dipole resonance to improve the detection sensitivity of biosensors.Methods The metasurface had its structure and dimensions designed according to its operating frequency band of graphene metasurface and the principle of toroidal dipole generation,which was modeled using finite element simulation software.The transmission spectra of the metasurface in the operating frequency band and its surface electric field and surface current distributions at the resonant frequency were analyzed;a biofilm with variable refractive index used to simulate the microbial sample was placed on the metasurface,and the frequency shift of the transmission spectrum caused by the change of the refractive index unit of the biofilm was calculated,and then the detection sensitivity of the metasurface was deduced.Results The metasurface designed excited toroidal dipole resonance successfully.Simulation calculations showed that the sensitivity of the metasurface at the resonance was about 42 GHz/RIU.Conclusion The metasurface designed has a high quality factor and improves the detection sensitivity efficiently,which lays a foundation for the design and optimization of patterned graphene biosensors based on toroidal dipole resonance.