Gold nanosphere propulsion by using femtosecond laser-excited enhanced near field
Gold nanosphere propulsion by using femtosecond laser-excited enhanced near field
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DOI：
10.1007/s00339-014-8328-0
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发表时间：
2014-03
期刊：
影响因子：
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通讯作者：
T. Shinohara;M. Terakawa
中科院分区：
文献类型：
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作者：
T. Shinohara;M. Terakawa
在理论计算和实验研究的基础上，提出了利用飞秒激光增强近场推进纳米球。用三维时域有限差分方法模拟了硅衬底上金纳米球周围的光强分布和增强。根据光强分布计算了球体的速度和推进角。在我们的模拟中，我们计算了直径在100到600 nm之间的金纳米球的光学强度。计算结果表明，在直径为100~250 nm的范围内，球体的速度基本不变，而直径大于250 nm时，球体的速度有所下降。通过改变p极化波的入射角度，可以将推进角控制到仅4.6°。我们已经在实验中演示了金纳米球的推进。我们的实验中使用了直径为200 nm的金纳米球。被推进的金粒子已被激光熔化并沉积在接收器基板上。研究了金颗粒的大小和空间分布。减小激光光斑尺寸和施主与受主衬底之间的间距，可以实现金粒子在受主衬底上存在区域的缩小。
We propose nanosphere propulsion by using femtosecond laser-excited enhanced near field based on the theoretical calculations and experimental study. The optical intensity distribution and enhancement around a gold nanosphere on a silicon substrate was simulated by a 3D finite-difference time-domain method. The sphere velocities and propelled angles were calculated based on the optical intensity distribution. In our simulation, we calculated the optical intensity for the gold nanospheres with a diameter ranging from 100 to 600 nm. Calculation results show that the sphere velocity was fairly constant for the diameters ranging from 100 to 250 nm, while the velocity decreased for diameters larger than 250 nm. The propelled angle could be controlled up to only 4.6° by varying the incident angles of p-polarized waves. We have demonstrated the gold nanosphere propulsion in experiment. The gold nanospheres with a diameter of 200 nm were used in our experiments. The propelled gold particles have been melted by laser irradiation and deposited on the receiver substrate. The size and spatial distributions of gold particles have been investigated. The decrease in the laser spot size and the gap distance between the donor and receiver substrate would realize the reduction in the existence region of gold particles on the receiver substrate.