Development of a Scanning Near-field Infrared Microscope Based on a Free Electron Laser

提供资金用于开发最先进的扫描近场红外显微镜，该显微镜涉及使用高度准直、可调谐的红外源，如自由电子激光。该仪器有望在材料科学和生物系统中有许多应用，因为它结合了红外光谱的高光谱分辨率和低至0.05微米的高分辨率成像，而不会影响传统红外光谱的频率分辨率。此外，红外固有的大特征吸收系数意味着可以获得对比度高达105分之一的图像，而不需要求助于任何染色过程。所提出的显微镜应能满足人们长期以来对成像技术的需求，这种成像技术能够无损地识别表面的化学成分。长期以来，人们一直认为，红外光谱与成像的结合将为无损检测表面提供一种有价值的技术。然而，当与传统成像技术一起使用时，这种技术的前景受到了红外线长波辐射设置的低空间分辨率的限制。在这项工作中，利用光学近场扫描探针显微镜的最新突破，以及自由电子激光等高准直、可调红外光源的可用性，构建了一种可以达到0.05微米空间分辨率的红外近场显微光谱仪。这种新颖的仪器有可能给材料的表征带来革命性的变化。

Funds are provided for the development of a state-of-art scanning near-field infrared microscope that involves the use of highly collimated, tunable infrared sources such as free electron lasers. This instrument is expected to have many applications in both materials science and biological systems, because it combines the exquisite spectral resolution of infrared spectroscopy with high-resolution imaging down to 0.05 micrometers without compromising on the frequency resolution of conventional IR spectroscopy. Furthermore, the intrinsically large characteristic absorption coefficients in the infrared mean that it is possible to obtain images with contrast as large as 1 part in 105 without resorting to any staining procedures. The proposed microscope should satisfy a long-felt need for an imaging technique that is capable of non-destructive identification of the chemical composition of surfaces. %%% It has long been appreciated that the combination of infrared spectroscopy with imaging would provide a valuable technique for examining surfaces non-destructively. However, the promise of this technique was limited by the poor spatial resolution set by the long wavelengths of the infrared radiation when used with conventional imaging techniques. In this work, the recent breakthroughs in optical near-field scanning probe microscopy, and the availability of highly collimated, tunable infrared sources such as free electron lasers, are used to construct an infrared near-field microspectroscope that can achieve a spatial resolution of 0.05 micrometers. This novel instrument has the potential for revolutionizing the characterization of materials.