微球透镜阵列并行制造表面增强拉曼衬底及其光谱增强研究  

Parallel-laser nanofabrication of surface-enhanced Raman spectroscopy(SERS)substrates by microsphere-lens array for ultrasensitive trace-detection

作　　者：王梦圆 赵晨[1] 闫胤洲[1] 赵艳[1] 蒋毅坚[1] WANG Mengyuan;ZHAO Chen;YAN Yinzhou;ZHAO Yan;JIANG Yijian(School of Physics and Optoelectronic Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学,物理与光电工程学院,北京100124

出　　处：《光散射学报》2024年第1期28-37,共10页The Journal of Light Scattering

基　　金：国家自然科学基金面上项目(12374339),北京市科技新星计划资助(20230484468),北京市教委科技计划重点项目(KZ202110005002)。

摘　　要：SERS作为一种高灵敏物质指纹谱分析技术,在生物传感、化学分析等领域具有广泛的应用。具有规整纳米结构的SERS衬底是保证拉曼光谱痕量检测可靠性和稳定性的前提,实现高精度、大尺度和高效率的微纳结构制造是SERS衬底目前亟需突破的技术瓶颈。本工作提出了介质微球透镜—金纳米孔(ML/AuNHs)阵列复合SERS衬底新结构与制造新方法。首先,利用介质微球透镜光子纳米射流,在沉积于微球底部的金膜上制备纳米孔结构,形成ML/AuNHs复合结构。系统研究了532 nm纳秒脉冲激光能量、微球透镜直径、金膜厚度等工艺参数对金纳米孔的成形规律,通过优化加工工艺,实现了微球透镜阵列底部直径215 nm金纳米孔的超分辨并行加工。之后,理论分析了微球透镜的SERS“热点”自对准聚焦、光学回音壁共振模式以及定向天线等光场调控过程,揭示了ML/AuNHs复合衬底的拉曼增强机制。最后,展示了ML/AuNHs复合衬底检出灵敏度10-10 M(硝基苯硫酚,4-NBT)的SERS检测能力,较单独使用金属纳米孔降低2个数量级。本工作提供了一种简易高效且具有高灵敏度的SERS衬底结构及其制备方法,拓宽了SERS的实际应用潜力。Surface-enhanced Raman spectroscopy(SERS)is a powerful technique for fingerprinting analysis of substances,which has been widely used in biosensing and chemical analysis.The fabrication of SERS substrates with well-ordered nanostructures is crucial for high reliability and stability in Raman trace-detection.The development of precise,large-scale,and efficient fabrication methods for nanostructured substrates is still a challenge to SERS used in practice so far.In this work,we propose a parallel-laser nanofabrication method for nanostructure arrays,combining microsphere-lenses with gold nanoholes(ML/AuNHs)for ultrasensitive hybrid SERS substrates.The AuNHs are fabricated on the bottom surfaces of ML by the photonic nanojets for the hybrid structures.The effect of process parameters,i.e.,the pulsed laser energy,the ML diameter,and the thickness of gold film,on the quality of the nanoholes is investigated.The parameters of laser fabrication are optimized for the diameter of AuNHs down to 215 nm.Furthermore,the optical regulation in ML/AuNHs is theoretically investigated,including self-aligned focusing to the hotspots,optical whispering-gallery modes(WGMs),and directional antenna.The mechanism of Raman enhancement via the ML/AuNHs is therefore revealed.The limit of detection by the ML/AuNHs down to 10-10 M for 4-nitrobenzenethiol(4-NBT)molecules is also demonstrated,which is two orders of magnitude lower than using the AuNHs without ML coupling.This work presents a simple and efficient parallel-laser nanofabrication method for the highly-sensitive SERS substrates in the future applications.

关 键 词：表面增强拉曼光谱 超分辨并行加工 微球透镜阵列 光子纳米射流 局域表面等离激元 

分 类 号：O657.37[理学—分析化学]