In the diagnosis of severe contagious diseases such as Ebola, severe acute respiratory syndrome, and COVID-19, there is an urgent need for protein sensors with large refractive index sensitivities. Current terahertz metamaterials cannot be used to develop such protein sensors due to their low refractive index sensitivities. A simple method is proposed that is compatible with all geometrical structures of terahertz metamaterials to increase their refractive index sensitivities. This method uses patterned photoresist to float the split-ring resonators (SRRs) of a terahertz metamaterial at a height of 30 μm from its substrate that is deposited with complementary SRRs. The floating terahertz metamaterial has an extremely large refractive index sensitivity of 532 GHz/RIU because its near field is not distributed over the substrate and also because the complementary SRRs confine the field above the substrate. The floating terahertz metamaterial senses bovine serum albumin (BSA) and the protein binding of BSA and anti-BSA as BSA, and anti-BSA solutions with low concentrations that are smaller than 0.150 μmol/L are sequentially dropped onto it. The floating terahertz metamaterial is a great achievement to develop protein sensors with extremely large refractive index sensitivities, and has the potential to sense dangerous viruses.

中文翻译：

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具有极高折射率灵敏度的浮动太赫兹超材料

在埃博拉、严重急性呼吸系统综合症和 COVID-19 等严重传染性疾病的诊断中，迫切需要具有大折射率敏感性的蛋白质传感器。由于其低折射率敏感性，目前的太赫兹超材料不能用于开发此类蛋白质传感器。提出了一种与太赫兹超材料的所有几何结构兼容的简单方法，以增加其折射率灵敏度。该方法使用图案化光刻胶将太赫兹超材料的裂环谐振器 (SRR) 浮动在距其衬底 30 μm 的高度处，该衬底沉积有互补 SRR。浮动太赫兹超材料具有 532 GHz/RIU 的极高折射率灵敏度，因为其近场未分布在基板上，而且互补 SRR 将场限制在基板上方。漂浮的太赫兹超材料将牛血清白蛋白（BSA）和BSA与抗BSA的蛋白质结合作为BSA，依次滴加小于0.150 μmol/L的低浓度抗BSA溶液。浮动太赫兹超材料是开发具有极高折射率敏感性的蛋白质传感器的一项重大成就，并具有感知危险病毒的潜力。并依次滴加小于0.150 μmol/L的低浓度抗BSA溶液。浮动太赫兹超材料是开发具有极高折射率敏感性的蛋白质传感器的一项重大成就，并具有感知危险病毒的潜力。并依次滴加小于0.150 μmol/L的低浓度抗BSA溶液。浮动太赫兹超材料是开发具有极高折射率敏感性的蛋白质传感器的一项重大成就，并具有感知危险病毒的潜力。