Optical microscopy imaging modes

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]. 

Transmission electron microscopy (TEM) resembles optical microscopy, except that electromagnetic instead of optical lenses are used to focus an electron beam on the sample. Two modes are available in TEM, a bright-freld mode where the intensity of the transmitted beam provides a two-dimensional image of the density or thickness of the sample, and a dark-field mode where the electron diffraction pattern is recorded. A combination of topographic and crystallographic information, including particle size distributions, can be obtained in this way [32],... 

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. 

Sherar, M. D., Noss, M. B., and Foster, F. S. (1987). Ultrasound backscatter microscopy images the internal structure of living tumour spheroids. Nature 330,493-5. [174] Shimada, H. (1987). Propagation of multi-mode ultrasonic pulses in non-destructive material evaluation. In Ultrasonic spectroscopy and its application to Materials science (ed. Y. Wada), pp. 50-6. Ministry of Education, Science and Culture, Japan. [148] Shotton, D. M. (1989). Confocal scanning optical microscopy and its applications for biological specimens. J. Cell. Sci. 94,175-206. [177,200]... 

Sackrow M, Stanciu C, Lieb MA, Meixner AJ (2008) Imaging nanometre-sized hot spots on smooth Au Aims with high-resolution tip-enhanced luminescence and Raman near-fleld optical microscopy. Chemphyschem 9(2) 316-320 93. Berweger S, Raschke MB (2009) Polar phonon mode selection rules in tip-enhanced Raman scattering. J Raman Spectrosc 40(10) 1413-1419... 

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. ... 

When the diffusion is very slow and high spatial resolution is more important than high frame rates, such as in a polymer film, illumination mode scanning near-field optical microscopy can be used to image the diffusion of individual fluorophores. This application will be discussed in the Section V.B. 

Optical microscopy on phase contrast mode allows observation of the different morphologies obtained for each PP/interfacial modifier/PA6 blend. By image analysis techniques, it is possible to carry out statistical field measurements not only of the mean number of particles on the dispersed phase but also of their preferential geometry, mean size, and size distribution. 

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