Electron Microscopes

Electron microscopes utilize electron beams instead of light and thus are able to achieve greater resolution (Figure 11.8). The two major types are the transmission electron microscope (TEM) and the scanning electron microscope (SEM).

The TEM is analogous to a light microscope, with a beam of electrons being transmitted through the sample rather than light. Instead of glass lenses, the TEM uses electromagnets to control and focus the beam. The result is the potential for much higher magnification, with levels of resolution down to a few tenths of a nanometer (nearly 1000 times better than what can be achieved with a light microscope).

Figure 11.6 Fluorescence microscopy: a fluorescent image is viewed against a darkened or black background.

Figure 11.7 Stage micrometer used to calibrate dimensions under microscope.

Mercury vapor arc lamp

Ocular lens

Ocular lens

Mercury vapor arc lamp

Figure 11.6 Fluorescence microscopy: a fluorescent image is viewed against a darkened or black background.

Electron Microscopes

Light

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