Mechanism of Prism-Coupled Scanning Tunneling Microscope Light Emission
Mechanism of Prism-Coupled Scanning Tunneling Microscope Light Emission
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DOI：
10.1143/jjap.50.095201
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发表时间：
2011-09
影响因子：
1.5
通讯作者：
Wataru Iida;J. U. Ahamed;S. Katano;Y. Uehara
中科院分区：
文献类型：
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作者：
Wataru Iida;J. U. Ahamed;S. Katano;Y. Uehara
利用时域有限差分法研究了棱镜耦合结构中扫描隧道显微镜的发光机制。在该配置中，样品是在半球形玻璃棱镜的底表面上蒸发的金属薄膜。测量通过金属膜发射到棱镜中的STM光（棱镜侧发射）。由于局域表面等离子体激元（LSP）和表面等离子体激元（SPP）有助于棱镜侧发射，这种发射是强于传统的STM-LE从样品表面侧测量，这是由LSP单独辐射。我们表明，棱镜侧发射的空间分辨率不是由SPP的传播长度决定的，而是由LSP的横向尺寸决定的，类似于传统的（即，头端侧）STM-LE。因此，我们得出结论，通过使用棱镜耦合配置，STM-LE的信号电平提高，而不会损失在尖端侧发射中获得的空间分辨率。
We have investigated the mechanism of scanning tunneling microscope light emission (STM-LE) in a prism-coupled configuration using finite difference time domain analysis. In this configuration, the sample is a metallic thin film evaporated on the bottom surface of a hemispherical glass prism. STM light emitted into the prism (prism-side emission) through the metallic film is measured. Since both localized surface plasmons (LSP) and surface plasmon polaritons (SPP) contribute to prism-side emission, this emission is stronger than that in conventional STM-LE measured from the sample surface side, which is radiated by LSP alone. We show that the spatial resolution of prism-side emission is determined not by the propagation length of SPP, but by the lateral size of LSP, similarly to conventional (i.e., tip side) STM-LE. Thus, we conclude that, by using the prism-coupled configuration, the signal level of STM-LE improves without the loss of spatial resolution attained in tip side emission.