| Popis: |
Publisher Summary This chapter focuses on Raman microscopy and other local analysis techniques. In Raman microspectrometry, two main questions must be considered: (1) how to localize the area to be analyzed, and (2) how to analyze the area in question. To localize an area as small as 0.5-0.25 mm in size, the human eye is sufficient, but when the area is smaller than 0.25 mm, an optical system which is capable of delivering a magnified and contrasted image to the eye is necessary. To analyze the area of interest the analytical system may be the same as that employed in the imaging technique, or quite different. In general, the two main characteristics of imaging and analyzing are related. These are the lateral resolving power or lateral image resolution and the axial resolution or depth of field. The lateral resolving power takes into account the lower limit for the human eye, which is approximately 0.25 mm; this condition defines the necessary magnification and the smallest area to be localized at the sample surface. The axial resolution together with lateral resolution determines the analyzed volume. It depends not only on the optical characteristics of the system, but also on the nature of the sample. The chapter summarizes some of the basic features of electron optics and also reviews the coupling of Raman and electron microscopies. |
