论文类型：期刊论文
发表刊物：Photonics Research
收录刊物：SCI
所属单位：华中科技大学
刊物所在地：中国
学科门类：工学
一级学科：光学工程
项目来源：国基金
卷号：10
期号：1
页面范围：高被引论文
ISSN号：2327-9125
DOI码：10.1364/PRJ.444490
发表时间：2021-12-13
影响因子：7.0
教研室：武汉光电国家研究中心
摘要：Plasmonic sensing based on nanostructures is a powerful analytical tool for ultrasensitive label-free biomolecule detection that holds great potential in the field of clinical diagnostics and biomedical research. Here, we report the fabrication, the characterization, and the principle of operation of gold nanorod hyperbolic metamaterials (NHMMs) along with ultrasensitive bulk refractive index and label-free biomolecular detection. By combining electron-beam lithography and nanoscale electroplating, we demonstrate the fabrication of a highly ordered, height-controllable, and vertical array of nanorods. By exciting the bulk plasmon–polariton mode in the NHMM using a prism-coupling technique and integrating the sensor in microfluidics, we demonstrate that the bulk sensitivity and figure of merit of our device could reach 41,600 nm/RIU and 416 RIU-1, respectively. The physical mechanism of this high bulk sensitivity is revealed through theoretical and experimental studies. Moreover, by bio-functionalizing the surface of the NHMM sensor, monitoring the binding of streptavidin at dilute concentrations is performed in real time. We test different concentrations of streptavidin ranging from 200 to 5 μg/mL, and the NHMM biosensor exhibits a 1 nm wavelength shift for a 5 μg/mL streptavidin detection. By fitting the Hill equation of the NHMM biosensor and taking into account the level of noise (0.05 nm) as the minimum wavelength shift of the detectable limit, the limit of detection of the NHMM biosensor to streptavidin can be estimated to be 0.14 μg/mL (2.4 nm). As a direct comparison, a 0.5 nm wavelength shift for 20 μg/mL of streptavidin is reported when using a conventional gold film sensor under identical experimental conditions. The developed plasmonic NHMM sensor shows tremendous potential for highly sensitive bulk solutions and biomolecule detection and provides a promising avenue for free-label biosensing applications in the future.