An evaluation of the application of the aperture infrared SNOM technique to biomedical imaging
An evaluation of the application of the aperture infrared SNOM technique to biomedical imaging
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DOI：
10.1088/2057-1976/aaa0de
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发表时间：
2018-03-01
影响因子：
1.4
通讯作者：
Weightman, P.
中科院分区：
文献类型：
--
作者：
Ingham, J.;Pilling, M. J.;Weightman, P.
采用孔径红外扫描近场光学显微镜（IR-SNOM）对单个人食管腺癌细胞（OE33）进行了透射和反射成像，并采用傅里叶变换红外光谱（FTIR）对其进行了透射和反射成像。这项工作提出了在同一样品的透射和反射中使用孔径IR-SNOM技术获得的第一张图像。结果用于比较两种SNOM模式以及两种具有互补功能的技术。SNOM技术需要非常稳定的光源和仔细选择波长，因为它太慢，无法产生用FTIR获得的数千个波长的图像。然而，SNOM技术没有衍射限制，通过精心制作尖端可以产生高空间分辨率的图像。透射和反射SNOM图像之间没有明显的相关性，不同波长图像之间的相关性随成像方式的不同而不同。这些结果归因于倏逝波对波长和样品内尖端与信号源之间距离的强烈依赖。虽然透射和反射SNOM图像都显示与地形有一定的相关性，但这不是主要的影响。这些结果表明，通过适当的校准，反射和透射孔径IR-SNOM测量的组合有可能揭示样品化学结构的深度分布信息。
Asingle human oesophageal adenocarcinoma cell (OE33) has been imaged using aperture infrared scanning near-field optical microscopy (IR-SNOM) in transmission and reflection and also by Fourier-transform infrared (FTIR) microspectroscopy in transmission only. This work presents the first images obtained in both transmission and reflection of the same specimen using the aperture IR-SNOM technique. The results have been used to compare the two SNOM modes and also the two techniques, which have complementary capabilities. The SNOM technique necessitates a very stable source and a careful choice of wavelengths, since it is too slow to yield images at the thousands of wavelengths obtained with FTIR. However the SNOM technique is not diffraction limited and with careful fabrication of tips can yield images with high spatial resolution. There is no significant correlation between the SNOM images obtained in transmission and reflection and the correlations between images obtained at different wavelengths vary with the different imaging modes. These results are attributed to the strong dependence of the evanescent wave on both the wavelength and the distance between the tip and the source of the signal within the sample. While both transmission and reflection SNOM images show some correlation with topography this is not a dominant effect. These results indicate that with suitable calibration a combination of reflection and transmission aperture IR-SNOM measurements has the potential to reveal information on the depth distribution of the chemical structure of a specimen.