基于准BIC的全介质超表面的局域电场增强及其应用研究

通过增强局域电场可以研究光与物质的相互作用。目前常用金属微纳结构增强上转换纳米粒子发光和与声子的强耦合，但是面临着金属固有损耗较大的问题。因此低损耗的全介质超表面在此方面具有很高的研究意义。具有高Q值的准连续体中的束缚态（BIC）可以极大提高全介质超表面的局域电场增强，对发光器件和传感器等诸多领域有重要意义。本项目研究全介质超表面的参数对准BIC的Q值和局域电场增强的影响。面向增强上转换纳米粒子发光和与声子强耦合的两个应用，研究并设计具有双准BIC和中红外准BIC的全介质超表面，重点研究基于准BIC的超表面在增强光与纳米粒子和声子相互作用的性质。以期实现上转换纳米粒子的发光增强和超表面与声子共振的强耦合，提高上转换纳米粒子和声子极化子在生物成像、生物传感等领域的应用潜力。深入研究这些内容，有助于不断完善和发展基于准BIC的全介质超表面在增强光与物质相互作用、发光增强和中红外光学器件的应用。

By enhancing local electric fields can study the interactions between light and matter. While metal micro/nanostructures are commonly used to enhance the upconversion nanoparticles and strong coupling with phonons, it is faced with the problem of high intrinsic loss of the metal materials. Therefore, it is much meaningful to study the all-dielectric metasurface with low loss. The quasi bound states in a continuum (BIC) with high Q value can greatly improve the local electric field enhancement of the metasurface, which has great significance in many fields such as light-emitting devices and sensors. This project intends to study the effects of different parameters of the metasurface on the Q value and the local electric field enhancement. For two applications of enhancing the upconversion nanoparticles and strong coupled with phonon resonance, we study and design the double quasi-BIC and infrared quasi-BIC all-dielectric metasurfaces, key study the metasurfaces based on quasi-BIC in modulating the local field and enhancing the interactions between light and nanoparticles/phonons, in order to achieve brightening upconversion nanoparticles and strong coupled with phonon resonance and improve the potential in applications of upconversion nanoparticles and phonon polaron in biological imaging and biosensors. These results will definitely improve and develop the applications of all-dielectric metasurfaces based on quasi-BIC in enhancing light-matter interactions, fluorescence signals enhancement and mid-infrared optical devices.