Near-field properties of a gold nanoparticle array on different substrates excited by a femtosecond laser
Near-field properties of a gold nanoparticle array on different substrates excited by a femtosecond laser
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DOI：
10.1088/0957-4484/18/30/305703
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发表时间：
2007-08
期刊：
影响因子：
3.5
通讯作者：
N. Nedyalkov;P. Atanasov;M. Obara
中科院分区：
文献类型：
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作者：
N. Nedyalkov;P. Atanasov;M. Obara
在本文中，我们提出了 800 nm 超短激光脉冲激发的金纳米颗粒近场区电磁场特性的实验和理论结果。研究了单个孤立粒子和二维纳米粒子阵列情况的近场特性。颗粒沉积在不同的基材上：金属 (Au)、半导体 (Si) 和电介质 (SiO2)。基于有限差分时域 (FDTD) 模拟技术的计算预测，颗粒附近的场会增强，因为场强的大小取决于基底材料和 2D 阵列的颗粒间距离。对于金基底上紧密排列的纳米粒子，最大场强比单个粒子低两倍以上。随着200 nm直径金颗粒之间距离的增加，场强值增加，直至距离约800 nm。基板上场增强的理论预测得到了实验的证实。用钛蓝宝石激光器的单个激光脉冲照射沉积在三种不同基底上的纳米颗粒，导致纳米孔的形成。讨论了观察到的特性。
In this paper we present experimental and theoretical results on the properties of the electromagnetic field in the near-field zone of gold nanoparticles excited by an 800 nm ultrashort laser pulse. The near-field properties are studied for the case of a single isolated particle and 2D nanoparticle array case. Particles are deposited on different substrates: metal (Au), semiconductor (Si) and dielectric (SiO2). The calculations based on the finite difference time domain (FDTD) simulation technique predict that the field in the vicinity of the particles is enhanced as the magnitude of the field intensity depends on the substrate material and the interparticle distance for 2D array. For closely arrayed nanoparticles on the gold substrate, the maximal field intensity is more than two times lower than that of a single particle. With the increase of the distance between 200 nm diameter gold particles, the value of the field intensity increases up to a distance of about 800 nm. The theoretical prediction of the field enhancement on the substrate is confirmed experimentally. The irradiation of the nanoparticles deposited on the three different substrates with a single laser pulse of a Ti:sapphire laser results in a nanohole formation. Discussion on the observed properties is presented.