Imaging modes, optical

Figure 1 Diagrams showing the essential electron-optical configurations used for various imaging modes in CTEM and STEM as seen by two points A and B on the sample, (a) CTEM axial bright field, (b) CTEM tilted dark field, (c) CTEM hollow cone dark field, and (d) STEM with bright field and annular dark field detectors.

A number of methods are available for the characterization and examination of SAMs as well as for the observation of the reactions with the immobilized biomolecules. Only some of these methods are mentioned briefly here. These include surface plasmon resonance (SPR) [46], quartz crystal microbalance (QCM) [47,48], ellipsometry [12,49], contact angle measurement [50], infrared spectroscopy (FT-IR) [51,52], Raman spectroscopy [53], scanning tunneling microscopy (STM) [54], atomic force microscopy (AFM) [55,56], sum frequency spectroscopy. X-ray photoelectron spectroscopy (XPS) [57, 58], surface acoustic wave and acoustic plate mode devices, confocal imaging and optical microscopy, low-angle X-ray reflectometry, electrochemical methods [59] and Raster electron microscopy [60]. 

The electron-optical techniques are increasingly often being applied under conditions of ultra high vacuum, allowing the study of surfaces under controlled circumstances. The most significant developments for electron microscopy however have been in the imaging mode where considerable enhancement of resolution has occurred, leading to various forms of operation. 

To produce a high-resolution lattice image of a crystal, at least two beams must be allowed to pass through the aperture in the back focal plane of the objective lens. The basic optical principles involved in this imaging mode are discussed in Chapter 1. However, a number of factors not discussed there influence high-resolution TEM images these are the main concern of Chapter 6. 

Hatano H, Inouye Y, Kawata S (1997) Near-field optical microscope with a multiheight scanning-imaging mode. Opt Lett 22 1532... 

Figure 3.4 Optical paths of (a) diffraction mode and (b) image mode. SAD, selected area diffraction aperture.

For more details on the above imaging modes and more specialized optical techniques the reader is referred to Applied polymer light microscopy by D. A. Heiiisley. ... 

The specimen is unloaded from the mass spectrometer and a transmission mode optical image is taken with a digital camera coupled to an optical microscope. If several optical... 

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