Tiwari Pradeep, Kala Deepak, Sakowicz Maciej
Institute of High Pressure Physics PAS, CENTERA Laboratories, Sokolowska 29/37, 01-142, Warsaw, Poland.
Sci Rep. 2025 Aug 13;15(1):29749. doi: 10.1038/s41598-025-15669-3.
This article explores the impact of substrate choice on the sensitivity of sensors that utilize metallic terahertz metasurfaces as the actuating element. While terahertz metasurfaces represent a rapidly evolving field, fundamental research remains essential and highly impactful. A critical component of any metasurface is the dielectric substrate on which it is fabricated - a factor that holds significance across all spectral ranges. This work focuses specifically on metallic terahertz metasurfaces operating in transmission mode. It provides an overview of various substrates (Ge, Si, SiO₂, TPX) and discusses design principles for such metasurfaces, including magnetic and electric dipole surface plasmon resonances, Fano resonances, and quasi-bound states in the continuum. We initially simulated the structures using COMSOL Multiphysics software and then confirmed the results experimentally by detecting various concentrations of bovine serum albumin. Our study systematically examines how real-metal modeling and substrate selection influence the Q-factor and sensing performance, in contrast to earlier research that either fixed the substrate type or modeled the metal as a perfect electric conductor. This dual approach provides valuable guidance for designing high-Q, low-loss terahertz metasurface biosensors. Our results demonstrate that for all types of terahertz metasurfaces operating in transmission mode, using a low-refractive-index substrate enhances sensor sensitivity, making it the preferred choice for sensing applications. This opens new prospects for the design of high-sensitivity biosensors.
本文探讨了衬底选择对以金属太赫兹超表面作为驱动元件的传感器灵敏度的影响。虽然太赫兹超表面是一个快速发展的领域，但基础研究仍然至关重要且具有高度影响力。任何超表面的一个关键组件是其制造所基于的介电衬底——这一因素在所有光谱范围内都具有重要意义。这项工作特别关注工作在透射模式下的金属太赫兹超表面。它概述了各种衬底（锗、硅、二氧化硅、聚4-甲基-1-戊烯），并讨论了此类超表面的设计原理，包括磁偶极和电偶极表面等离子体共振、法诺共振以及连续谱中的准束缚态。我们最初使用COMSOL Multiphysics软件对结构进行了模拟，然后通过检测不同浓度的牛血清白蛋白对结果进行了实验验证。与早期要么固定衬底类型要么将金属建模为理想导体的研究相比，我们的研究系统地考察了实际金属建模和衬底选择如何影响品质因数和传感性能。这种双重方法为设计高Q值、低损耗的太赫兹超表面生物传感器提供了有价值的指导。我们的结果表明，对于所有工作在透射模式下的太赫兹超表面类型，使用低折射率衬底可提高传感器灵敏度，使其成为传感应用的首选。这为高灵敏度生物传感器的设计开辟了新前景。
