Surface-enhanced Raman scattering (SERS) technique can increase the Raman signals of the analytes owing to the electric field enhancements on the nanostructures. The strong light intensity, called photonic nanojet, can be formed at the backlight of the dielectric microstructures. Recently, some researchers have applied the photonic nanojets in SERS. In this paper, a layer of synthesized low-cost polystyrene microspheres with the average of small particle size of 4.26 μm and high refractive index 1.5875 was prepared by dispersion polymerization method and coating on metal nanopillars SERS substrates using air-water interfacial floating method, and it was applied to improve the Raman signal sensitivity of kinetin (6-furfurylaminopurine) which is one kind of plant growth regulators and can function an effective compound for improving plant stress tolerance. The Raman intensity increased from 841 to 4449 for the Raman shift at 1327 cm−1, about 5.29 times stronger. The SERS experiments using the kinetin of ultralow concentrations are measured and it shows that femto Molar can be measured. The numerical simulations indicated that the enhancement factor was about 4 times for plane wave illumination and 3.1 times for focused Gaussian beam. It has considerable potential for different analytes in sensing applications.

中文翻译：

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基于光子纳米喷射和表面增强拉曼散射的激动素检测增强

由于纳米结构上的电场增强，表面增强拉曼散射（SERS）技术可以增加分析物的拉曼信号。称为光子纳米喷射的强光强度可以在介电微结构的背光处形成。最近，一些研究人员将光子纳米喷射应用于 SERS。本文采用分散聚合法制备了一层平均小粒径为4.26 μm、高折射率为1.5875的低成本合成聚苯乙烯微球，并采用气水界面漂浮法涂覆在金属纳米柱SERS基底上，并应用于提高激动素（6-糠基氨基嘌呤）的拉曼信号敏感性，激动素是一种植物生长调节剂，是提高植物抗逆性的有效化合物。对于 1327 cm-1 处的拉曼位移，拉曼强度从 841 增加到 4449，强约 5.29 倍。测量了使用超低浓度激动素的 SERS 实验，结果表明可以测量毫微微摩尔。数值模拟表明，平面波照明的增强因子约为4倍，聚焦高斯光束的增强因子约为3.1倍。它对传感应用中的不同分析物具有相当大的潜力。测量了使用超低浓度激动素的 SERS 实验，结果表明可以测量毫微微摩尔。数值模拟表明，平面波照明的增强因子约为4倍，聚焦高斯光束的增强因子约为3.1倍。它对传感应用中的不同分析物具有相当大的潜力。测量了使用超低浓度激动素的 SERS 实验，结果表明可以测量毫微微摩尔。数值模拟表明，平面波照明的增强因子约为4倍，聚焦高斯光束的增强因子约为3.1倍。它对传感应用中的不同分析物具有相当大的潜力。