Development of an Infrared Microscope for Three-dimensional Structural Study on Small Oritented Specimens

为了研究精细单晶、多晶单畴和细长聚合物薄膜等小取向试样的三维结构，研制了一种新型红外显微镜。设计了一种由旋转台和椭球镜组成的红外聚光镜来代替卡塞格伦聚光镜进行斜透射测量。有了这种聚光镜，大部分入射辐射可用于斜透射测量。效率比使用卡塞格伦冷凝器的测量高几倍。此外，可以选择任意入射方向，这对于试样取向变化非常困难的测量非常方便，例如在低温下使用低温恒温器进行测量。对于微FTIR光谱，防止MCT探测器的饱和是很重要的。为了调节入射辐射强度，采用了红外干扰滤光片。与通常使用狭缝或线栅的调节相反，干涉滤光片通过所需频率范围的红外辐射。因此可以用高强度的红外辐射来拍摄红外光谱，这使得SN比很高。电子显微镜也采用了金属丝网来保存标本。通过网格，入射辐射直接撞击试样，大大减少了杂散光。

For the three-dimensional structural study on small oriented specimens, such as, fine single crystals, single domains of polycrystalline specimens and elongated polymer films, an infrared microscope has been newly developed. In stead of the Cassegr ain condenser, an IR condenser consisting of a rotary stage and an ellipsoidal mirror was designed for oblique transmission measurement. With this condenser, most of the incident radiation can be utilized for the oblique transmission measurement. The efficiency is several times higher than the measurement using an Cassegr ain condenser. Furthermore, any incident direction can be selected, which is quite convenient for the measurement where the orientation change of specimens is very difficult, for example, the measurement at a low temperature using a cryostat.For micro FTIR spectroscopy, prevention of the saturation of MCT detectors is important. For the adjustment of the incident radiation intensity, IR interference filters were employed. Contrary to usual adjustment using a slit or wiregauze, interference filters pass the IR radiation of desired frequency range. So the IR spectra can be taken with IR radiation of high intensity, which makes SN ratio high.Wire grids for electron microscopes were also adopted for holding specimens. Through the mesh, the incident radiation directly impinges the specimen, which greatly reduces stray light.