In this article, a plasmonic gold nanoantenna is proposed as a sensor to monitor refractive index variations between 1.30 and 1.35. These values are defined since they are characteristic of, for instance, water-based solutions, DNA, or haemoglobin. To simulate the device a novel model is used, which takes advantage of the wave-particle dualism and the generalised Fresnel coefficients for absorbing media. Although it is a time-domain model, in this research work the model is improved to compute steady state and frequency-domain results. The response to a Dirac excitation is obtained using that novel model. The steady state is reached for a long pulse emission. The long pulse emission is emulated by a Dirac comb and consequently, the optical response of the device for this kind of excitation is obtained considering the sum of several Dirac's responses shifted in time. Then, steady state might be reached as suggested by the presented results. Taking into account the obtained pulse responses, the refractive index sensor for the range 1.30–1.35 is proposed. The obtained results suggest that 350 nm and 450 nm are the best wavelengths to detect these analyte variations. The sensitivity reaches values up to around 110%/RIU, but sensitivities around 80%/RIU are computed within the range 250–500 nm.

中文翻译：

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利用等离子体狭缝纳米天线的非凡光传输进行传感器应用

在本文中，提出了一种等离子体金纳米天线作为传感器来监测 1.30 至 1.35 之间的折射率变化。这些值的定义是因为它们是水基溶液、DNA 或血红蛋白等的特征。为了模拟该装置，使用了一种新颖的模型，该模型利用了波粒二元论和吸收介质的广义菲涅耳系数。尽管它是一个时域模型，但在本研究工作中，该模型经过改进以计算稳态和频域结果。使用该新颖模型获得了对狄拉克激励的响应。长脉冲发射达到稳定状态。长脉冲发射由狄拉克梳模拟，因此，考虑到随时间移动的多个狄拉克响应的总和，获得了设备对这种激发的光学响应。然后，如所呈现的结果所示，可能会达到稳定状态。考虑到获得的脉冲响应，建议使用范围为 1.30-1.35 的折射率传感器。获得的结果表明 350 nm 和 450 nm 是检测这些分析物变化的最佳波长。灵敏度最高可达 110%/RIU 左右，但在 250–500 nm 范围内计算出的灵敏度约为 80%/RIU。