Dark-field optical microscopy

Fig. 3 Schematic diagram of optical dark-field microscopy.

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],... 

Video microscopy has permitted direct observation of microtubule assembly/disassembly dynamics in vitro. Horio and HotanP first used dark-field optics to observe the growth and shrinkage phases, but so-called Allen video-enhanced contrast microscopy has become most convenient. 

What is dark-field microscopy How does it compare in terms of resolution and contrast with conventional optical microscopy ... 

Figure 2. Pitch coke 500°C75% l.telectron micros-copy on a section from the block observed by optical microscopy X 1800 photomontage (a) in bright field (b) in dark field...

Two techniques for overcoming the limitations of optical microscopy are of particular value in the study of colloidal systems. They are electron microscopy36-37, in which the limit of resolution is greatly extended, and dark-field microscopy, in which the minimum observable contrast is greatly reduced. 

Optical Contrast for Two-Dimensional Imaging Dark-Field Microscopy... 

Fig. 18.5 (a) Dark-field microscopy images of silver nanoparticles trapped in a microfluidic channel. The trapping wavelength was 830 nm. (b) Corresponding SERS spectra from the optically induced nanoparticle aggregates. A separate laser line at 514.5 nm was used to excite the Raman probes... 

Bright-Field Illumination A kind of illumination for microscopy in which the illumination of a specimen is arranged so that transmitted light remains in the optical path of the microscope and is used to form the magnified image. This is different from the arrangement in Dark-Field Illumination. 

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