Ultrasensitive detection of saccharides using terahertz sensor based on metallic nano-slits
Ultrasensitive detection of saccharides using terahertz sensor based on metallic nano-slits
复制标题
基于金属纳米狭缝的太赫兹传感器超灵敏检测糖类
DOI：
10.1038/s41598-020-60732-w
复制
发表时间：
2020-02-28
影响因子：
4.6
通讯作者：
Zhao, Zongshan
中科院分区：
文献类型：
--
作者：
Qin, Jianyuan;Cheng, Wei;Zhao, Zongshan
使用太赫兹光谱法在复杂背景中对痕量生物化学分子进行无生物学识别是极具挑战性的，因为这些分子在太赫兹范围内的吸收截面非常小。在这里，我们提出了一个太赫兹非共振纳米狭缝结构，作为一个强大的传感器。该结构在狭缝中表现出强烈增强的电场（五个数量级），以及在覆盖大多数分子特征频率的超宽频率范围内的高透射率。利用该狭缝结构可以清晰地检测到乳糖和麦芽糖的指纹特征，表明该狭缝结构可以在不改变其几何参数的情况下用于鉴别不同的乳糖和麦芽糖。具有200 nm厚度的乳糖和麦芽糖的吸收信号强度分别强烈增强了52.5和33.4倍。该结构对薄膜厚度非常敏感，适用于痕量样品的检测，当薄膜厚度小于250 nm时，可以根据吸收信号强度预测乳糖厚度。乳糖和麦芽糖混合物的检测表明，这种结构也可以实现多传感，这是很难实现的使用谐振结构。
Unambiguous identification of trace amounts of biochemical molecules in a complex background using terahertz spectroscopy is extremely challenging owing to the extremely small absorption cross sections of these molecules in the terahertz regime. Herein, we numerically propose a terahertz nonresonant nano-slits structure that serves as a powerful sensor. The structure exhibits strongly enhanced electric field in the slits (five orders of magnitude), as well as high transmittance over an extra-wide frequency range that covers the characteristic frequencies of most molecules. Fingerprint features of lactose and maltose are clearly detected using this slits structure, indicating that this structure can be used to identify different saccharides without changing its geometrical parameters. The absorption signal strengths of lactose and maltose with a thickness of 200 nm are strongly enhanced by factors of 52.5 and 33.4, respectively. This structure is very sensitive to thin thickness and is suitable for the detection of trace sample, and the lactose thickness can be predicted on the basis of absorption signal strength when the thickness is less than 250 nm. The detection of a mixture of lactose and maltose indicates that this structure can also achieve multi-sensing which is very difficult to realize by using the resonant structures.