EAGER: Highly sensitive optical biosensing using bound states in the continuum of high-Q all-dielectric metasurfaces

生物传感器是可以识别和定量检测生物分析物（可以分析的化学物质）的设备。 光学生物传感器通过将分析物的浓度转换为基于光的信号的变化来工作。在最近的大流行期间，这种敏感平台的重要性再次得到证明。该研究项目的目标是研究一种新型光学生物传感平台的原理，该平台可用作高灵敏度低成本的诊断工具，用于改善护理点设施的个性化和分层治疗。 传感器设计需要设计新颖的表面和特殊的分层反射镜，以产生分子振动，可以利用分子振动来测量分析物的浓度，检测限前所未有的低，这对于精确和早期检测病原体至关重要。 该方法不需要复杂的对准和稳定，这对于低成本和鲁棒的生物传感设备是有希望的。在该项目的框架内，与当地非营利组织的合作伙伴关系将为K-12学生提供机会，通过实验室图尔斯参观，职业讲座，科学博览会评审和其他教育活动扩大他们的STEM学习和职业。本研究的目标是研究全介质超颖表面中连续介质的光学束缚态，并探索其特性，以开发高灵敏度的光学生物传感器。目前，折射无标记生物传感通常基于谐振等离子体和超材料系统或更复杂的微谐振器和波导干涉仪。不幸的是，这些系统中的大多数要么不是非常敏感，要么依赖于需要稳定和精确对准的复杂且昂贵的平台。该项目将探索介电纳米腔的光磁偶极模式与布拉格反射镜的耦合，从而形成可用于光学传感的异常高品质因数谐振。与典型的国家的最先进的平台，这种新的方法实现了高品质因数的束缚态的连续不通过打破局部空间对称性，但通过耦合的光学模式，以他们的镜像。与现有解决方案相比，由此产生的共振有望在质量因子和检测限方面实现数量级的改进，为高灵敏度、可扩展、无需光谱仪、低成本的光学生物传感器铺平道路。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Biosensors are devices that can recognize and quantitatively detect biological analytes (chemical substances that can be analyzed). Optical biosensors work by converting the concentration of analytes to changes in light-based signals. The importance of such sensitive platforms has been demonstrated once again during the recent pandemic. The goal of this research project is to study the principles of a novel type of optical biosensing platform that can be used as highly sensitive low-cost diagnostic tools for improved personalized and stratified treatment at point of care facilities. The sensor design requires engineering of novel surfaces and special layered mirrors in order to create molecular vibrations that can be exploited to measure the concentration of analytes with unprecedentedly low limits of detection, which can be crucial for precise and early detection of pathogens. The approach does not require complex alignment and stabilization which is promising for low-cost and robust biosensing devices. In the framework of the project, a partnership with a local non-profit organization will provide opportunities for K-12 students to broaden their access to STEM learning and careers through lab tours, career talks, science fair judging and other educational activities. The goal of the research is to study optical bound states in the continuum in all-dielectric metasurfaces and explore their properties for the development of highly sensitive optical biosensors. Currently, refractometric label-free biosensing is typically based on resonant plasmonic and metamaterial systems or more complex microring resonators and waveguide interferometers. Unfortunately, most of these systems are either not very sensitive or rely on complex and costly platforms requiring stabilization and precise alignment. This project will explore the coupling of optical magnetic dipole mode of dielectric nanocavities to Bragg mirrors which lead to the formation of unusually high-quality factor resonances that can be used for optical sensing. Unlike the typical state-of-the-art platforms, this novel approach achieves high quality factor bound states in the continuum not via the breaking of local spatial symmetry but through coupling of the optical modes to their mirror image. The resultant resonances are expected to achieve an order of magnitude improvement in quality factors and limit of detection compared to the existing solutions, paving the way for highly sensitive, scalable, spectrometer-less, low-cost optical biosensors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.