基于准连续域束缚态介质超表面的光微流折射率传感研究

Optofluidic refractometric sensor based on quasi-bound states in the continuum in all-dielectric metasurface

准连续域束缚态(Quasi-BIC)是超表面中一种特殊共振模,具有极高的品质因子,可以极大地提高光与物质的相互作用,在荧光增强、纳米激光、光传感以及非线性光学等领域均有重要应用。本文基于我们前期对quasi-BIC产生的理论,研究quasi-BIC介质超表面在折射率传感方面的应用。本文给出了传感系统的基本结构,利用电子束光刻技术结合注塑工艺完成了样品光流控结构的制备,并初步测试性能。研究结果表明,得益于产生quasi-BIC的新方法,该超表面具有两个高Q值quasi-BIC共振峰(1.523μm和1.570μm,品质因子分别为3069和4071)。以四种折射率溶液(n分别为1.450/1.462/1.470/1.480)为样品的测试实验表明,两个共振峰均能完成折射率检测,灵敏度S分别为452 nm/RIU、428 nm/RIU,性能评价指标FOM分别为376.7、372,优于现有文献;共振波长和折射率之间线性度良好,展现了quasi-BIC超表面在折射率传感中的应用潜力。

The quasi-bound state in the continuum(quasi-BIC)is a special resonant mode in a metasurface with a very high quality factor that can greatly enhance the light-matter interaction and has important applications in fluorescence enhancement,nanolaser,optical sensing,and nonlinear optics.In this paper,we study the application of quasi-BIC dielectric metasurface for refractive index sensing based on the theory generated by our previous quasi-BIC.The basic structure of the sensing device is given,the preparation of the sample optofluidic structure is completed by using electron beam lithography combined with injection molding process,and the performance is initially tested.The results showed that the metasurface has two high-Q quasi-BIC resonance peaks(1.523μm and 1.570μm,with quality factors of 3069 and 4071,respectively),thanks to the new strategy of quasi-BIC generation.The test experiments with four refractive index solutions(n=1.450/1.462/1.470/1.480,respectively)as samples showed that both resonance peaks could complete the refractive index detection with the sensitivity of 452 nm/RIU and 428 nm/RIU,respectively,and the performance evaluation indexes FOM were 376.7 and 372,respectively,which are better than the existing literature.The linearity between resonance wavelength and refractive index is good,showing the potential of quasi-BIC metasurface in refractive index sensing.