Hajian Hodjat, Rukhlenko Ivan D, Bradley A Louise, Ozbay Ekmel
School of Physics, CRANN and AMBER, Trinity College Dublin, D02 PN40 Dublin, Ireland.
Institute of Photonics and Optical Science (IPOS), School of Physics, The University of Sydney, Camperdown, NSW 2006, Australia.
Micromachines (Basel). 2023 Feb 1;14(2):370. doi: 10.3390/mi14020370.
Among the transitional metal dichalcogenides (TMDCs), molybdenum disulfide (MoS) is considered an outstanding candidate for biosensing applications due to its high absorptivity and amenability to ionic current measurements. Dielectric metasurfaces have also emerged as a powerful platform for novel optical biosensing due to their low optical losses and strong near-field enhancements. Once functionalized with TMDCs, dielectric metasurfaces can also provide strong photon-exciton interactions. Here, we theoretically integrated a single layer of MoS into a CMOS-compatible asymmetric dielectric metasurface composed of TiO meta-atoms with a broken in-plane inversion symmetry on an SiO substrate. We numerically show that the designed MoS-integrated metasurface can function as a high-figure-of-merit (FoM=137.5 RIU-1) van der Waals-based biosensor due to the support of quasi-bound states in the continuum. Moreover, owing to the critical coupling of the magnetic dipole resonances of the metasurface and the A exciton of the single layer of MoS, one can achieve a 55% enhanced excitonic absorption by this two-port system. Therefore, the proposed design can function as an effective biosensor and is also practical for enhanced excitonic absorption and emission applications.
在过渡金属二硫属化物（TMDCs）中，二硫化钼（MoS）因其高吸收率和适用于离子电流测量而被认为是生物传感应用的杰出候选材料。介电超表面由于其低光学损耗和强近场增强效应，也已成为新型光学生物传感的强大平台。一旦用TMDCs进行功能化，介电超表面还可以提供强大的光子 - 激子相互作用。在这里，我们从理论上将单层MoS集成到一个与CMOS兼容的不对称介电超表面中，该超表面由在SiO衬底上具有面内反演对称性破缺的TiO元原子组成。我们通过数值模拟表明，由于连续态中的准束缚态的支持，所设计的集成MoS的超表面可以作为一种高品质因数（FoM = 137.5 RIU -1）的基于范德华力的生物传感器。此外，由于超表面的磁偶极共振与单层MoS的A激子的临界耦合，通过这个双端口系统可以实现55%的激子吸收增强。因此，所提出的设计可以作为一种有效的生物传感器，并且对于增强激子吸收和发射应用也具有实用性。
