Light, Nanomaterials & Nanotechnologies (L2n), CNRS-ERL 7004, Université de Technologie de Troyes, 10000 Troyes, France.
Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China.
Biosensors (Basel). 2022 Oct 12;12(10):866. doi: 10.3390/bios12100866.
In this paper, we demonstrated the ability of a plasmonic metasensor to detect ultra-low refractive index changes (in the order of ∆n = 10 RIU), using an innovative phase-change material, vanadium dioxide (VO), as the sensing layer. Different from current cumbersome plasmonic biosensing setups based on optical-phase-singularity measurement, our phase signal detection is based on the direct measurement of the phase-related lateral position shift (Goos-Hänchen) at the sensing interface. The high sensitivity (1.393 × 10 μm/RIU for ∆n = 10 RIU), based on the Goos-Hänchen lateral shift of the reflected wave, becomes significant when the sensor is excited at resonance, due to the near-zero reflectivity dip, which corresponds to the absolute dark point (lower than 10). GH shifts in the order of 2.997 × 10 μm were obtained using the optimal metasurface configuration. The surface plasmon resonance (SPR) curves (reflectivity, phase, GH) and electromagnetic simulations were derived using the MATLAB programming algorithm (by the transfer matrix method) and Comsol modeling (by finite element analysis), respectively. These results will provide a feasible way for the detection of cancer biomarkers.
在本文中，我们展示了等离子体超材料传感器检测超低折射率变化（约为 ∆n = 10 RIU）的能力，该传感器使用创新的相变材料氧化钒（VO）作为传感层。与目前基于光学相位奇点测量的繁琐等离子体生物传感装置不同，我们的相位信号检测基于对传感界面上相关相位横向位置偏移（古斯-汉欣）的直接测量。基于反射波的古斯-汉欣横向位移，灵敏度高达 1.393 × 10 μm/RIU（对于 ∆n = 10 RIU），当传感器在共振时被激发时，由于接近零的反射率下降，这对应于绝对暗点（低于 10），灵敏度变得非常显著。使用最佳的超表面结构，获得了约 2.997 × 10 μm 的 GH 偏移。表面等离子体共振（SPR）曲线（反射率、相位、GH）和电磁模拟分别使用 MATLAB 编程算法（通过传输矩阵方法）和 Comsol 建模（通过有限元分析）得出。这些结果将为癌症生物标志物的检测提供一种可行的方法。
