Surface Plasmon Resonance Enhanced Scanning Near-Field Pockels Microscope Observation of Polar Structure

表面等离子体共振增强扫描近场普克尔显微镜观察极性结构

基本信息

批准号：
15560002
负责人：
KAJIKAWA Kotaro
金额：
$ 2.05万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

We have developed a scanning near-field optical microscope that can image Pockels effects in ultrathin films such as a monomolecular layers. Pockels effect, sometimes called "linear electrooptic effect" is one of the second-order nonlinear optical processes that occur in a system without any inversion center under electric dipole approximation. Hence a polar structure can be probed with this technique. In addition, this microscope allows us to observe polar structure even in untrathin films because the surface plasmon resonance effect offers high sensitivity for the chance in the refractive index in a media. This promises possible observation of a small change in the refractive index i(<10^<-6>) in ultrathin films.The features of this microscope are :(1)an optical microscope that can prove the polar structure in a untrathin films.(2)the observation can be preformed without any high power lasers(3)we can make spectroscopic measurement easily.(4)we can prove nanometer sized region using a sharp tip.We have observed pattered dye-monomolecular layers adsorbed on a 45nm-thick thin gild film. The pattered size was 40x40μm. The Pockels images taken in the surface plasmon resonance condition were compared with the images obtained by second-harmonic generation microscopy that can also probe a polar structure, and confirmed a high correspondence between them. Although the present resolution is limited within about 10μm, it is likely that use of a sharp tip and a piezo stage with high resolution will provide much higher resolution.

我们开发了一种扫描近场光学显微镜，可以对超薄膜中的普克尔斯效应进行成像，例如单分子层普克尔斯效应，有时称为“线性电光效应”，是在不存在的系统中发生的二阶非线性光学过程之一。因此，可以用这种技术探测极性结构，即使在超薄的薄膜中，由于表面等离子体共振效应提供了高灵敏度。这使得可以观察到超薄膜中折射率 i(<10^<-6>) 的微小变化。该显微镜的特点是：(1) 光学显微镜。可以证明超薄薄膜中的极性结构。（2）无需任何高功率激光即可进行观察（3）我们可以轻松进行光谱测量。（4）我们可以使用锋利的尖端证明纳米尺寸的区域。我们有观察到的图案化的染料单分子层吸附在 45nm 厚的镀金薄膜上。图案化的尺寸为 40x40μm。将在表面等离子体共振条件下拍摄的 Pockels 图像与也可以探测极性结构的二次谐波产生显微镜获得的图像进行比较。，并证实了它们之间的高度对应性，尽管目前的分辨率限制在约 10μm 之内，但很可能使用尖锐的尖端和压电平台。具有高分辨率将提供更高的分辨率。