Hwang B S, Kwon M H, Kim Jeongyong
Department of Physics, University of Incheon, Dohwa-dong 177, Nam-ku, Incheon 402-749, Korea.
Microsc Res Tech. 2004 Aug;64(5-6):453-8. doi: 10.1002/jemt.20103.
We used the finite difference time domain (FDTD) method to study the use of scanning near field optical microscopy (SNOM) to locally excite the nanometric plasmonic waveguides. In our calculation, the light is funneled through a SNOM probe with a sub-wavelength optical aperture and is irradiated on one end of two types of plasmonic waveguides made of 50 nm Au sphere arrays and Au nanowires. The incident light was well localized at one end of the waveguides and consequently propagated toward the other end, due to the excitation of surface plasmon polaritons. We found that the propagation length of the nanosphere array type waveguide varies from 100 to 130 nm depending on the light wavelength, the size of the probe aperture, and the launching heights. Our result shows that reducing the aperture size and using the light of the plasmon resonance wavelength of the nanosphere array could increase the propagation length and, thus, the efficiency of electromagnetic energy transportation through nanosphere arrays.
我们使用时域有限差分（FDTD）方法来研究利用扫描近场光学显微镜（SNOM）对纳米等离子体波导进行局部激发。在我们的计算中，光通过具有亚波长光学孔径的SNOM探针汇聚，并照射在由50 nm金纳米球阵列和金纳米线制成的两种类型的等离子体波导的一端。由于表面等离激元极化子的激发，入射光很好地局域在波导的一端，并因此向另一端传播。我们发现，纳米球阵列型波导的传播长度根据光波长、探针孔径大小和发射高度在100到130 nm之间变化。我们的结果表明，减小孔径尺寸并使用纳米球阵列等离激元共振波长的光可以增加传播长度，从而提高通过纳米球阵列的电磁能量传输效率。
