Portes Ary V R, Martins Ana J L, Guerrero Jesus Alvarez, Carvalho Mauricio M, Amaya-Fernandez Ferney O, Saito Lúcia A M, Ramirez Jhonattan C
Department of Electronic Engineering, School of Engineering, Federal University of Minas Gerais (UFMG), Belo Horizonte 31270-901, MG, Brazil.
Faculty of Engineering, Universidad Libre, Av. 4 No. 12N-81, Cúcuta 540008, Colombia.
Polymers (Basel). 2021 Oct 15;13(20):3564. doi: 10.3390/polym13203564.
In this work, we present an interferometric polymer-based electro-optical device, integrated with an embedded double-monolayer graphene capacitor for biosensing applications. An external voltage across the capacitor applies an electric field to the graphene layers modifying their surface charge density and the Fermi level position in these layers. This in turn changes the electro-optic properties of the graphene layers making absorption in the waveguide tunable with external voltages. Simultaneously, it is possible to appreciate that this phenomenon contributes to the maximization of the light-graphene interaction by evanescent wave in the sensing area. As a result, it is obtained large phase changes at the output of the interferometer, as a function of small variations in the refractive index in the cladding area, which significantly increasing the sensitivity of the device. The optimum interaction length obtained was 1.24 cm considering a cladding refractive index of 1.33. An absorption change of 129 dB/mm was demonstrated. This result combined with the photonic device based on polymer technology may enable a low-cost solution for biosensing applications in Point of Care (PoC) platform.
在这项工作中，我们展示了一种基于聚合物的干涉式电光器件，该器件集成了用于生物传感应用的嵌入式双层石墨烯电容器。电容器两端的外部电压会对石墨烯层施加电场，从而改变其表面电荷密度以及这些层中的费米能级位置。这进而改变了石墨烯层的电光特性，使得波导中的吸收可通过外部电压进行调节。同时，可以认识到这种现象有助于通过传感区域中的倏逝波使光与石墨烯的相互作用最大化。结果，作为包层区域折射率小变化的函数，在干涉仪输出端获得了大的相位变化，这显著提高了器件的灵敏度。考虑到包层折射率为1.33，获得的最佳相互作用长度为1.24厘米。展示了129 dB/mm的吸收变化。这一结果与基于聚合物技术的光子器件相结合，可能为即时检测（PoC）平台中的生物传感应用提供一种低成本解决方案。
