Orientational imaging of single molecules by using azimuthal and radial polarizations.
Orientational imaging of single molecules by using azimuthal and radial polarizations.
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DOI：
10.1021/jp905719b
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
H. Ishitobi;I. Nakamura;N. Hayazawa;Z. Sekkat;S. Kawata
中科院分区：
文献类型：
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作者：
H. Ishitobi;I. Nakamura;N. Hayazawa;Z. Sekkat;S. Kawata
用聚焦的方位偏振光和径向偏振光测量了聚合物薄膜中单个荧光分子的三维分子取向，发现荧光强度与分子相对于薄膜表面的深度位置有关。我们发现，当与也由径向偏振激发但更靠近聚合物/空气界面的分子的荧光强度相比时，由径向偏振激发的膜中80 nm深的分子的荧光强度明显更大，这是在径向偏振激发下导致不同荧光强度的特征，对于具有相同极性取向但在膜内具有不同深度的分子。我们还发现，从一个分子内部的80 nm的薄膜在径向偏振的荧光强度的变化是明显大于一个在方位角偏振。这些发现证实了通过比较实验，使用不同厚度的薄膜与理论计算的电场分布。
Three-dimensional molecular orientations of single fluorescence molecules in polymeric thin films were measured by focused azimuthally and radially polarized light, in which we found that the fluorescence intensity was dependent on the depth position of the molecule with respect to the film surface. We found that the fluorescence intensity for a molecule which is 80 nm deep in the film excited by radial polarization is appreciably larger when compared with the fluorescence intensity for a molecule which is also excited by radial polarization but which is closer to the polymer/air interface, a feature which leads to different fluorescence intensities, under excitation by radial polarization, for molecules with the same polar orientation but with different depths inside the film. We also found that the variation of fluorescence intensity from a molecule inside an 80 nm film in radial polarization is appreciably larger compared with one in azimuthal polarization. These findings were confirmed by comparing experiments using different thickness films with theoretically calculated electric field distributions.