A biological microscope uses transmitted light for observation. However, different observation modes have been developed to use specific light characteristics for specific samples, such as transparent specimens and samples that do not pass light.
The table below shows the features of major observation modes. Each observation mode has been developed to properly use characteristics of light such as scattering, diffraction, polarization, interference, and fluorescence.
|Observation modes||Features||Common observation targets|
|Brightfield microscopy||A general observation mode for biological microscopes, which features a bright field-of-view with transmitted illumination||Living organisms, cells|
|Darkfield microscopy||Uses scattered light, not direct light, to make samples shine against a dark field-of-view||Microorganisms, cells|
|Phase contrast microscopy||Uses phase (light variations) to convert a sample to brightness contrast for observation||Colorless transparent samples, living cells|
|Polarized light microscopy||Illuminates a sample with polarized light to convert it to brightness or color contrast for observation||Crystals such as rocks and minerals, polymers|
|Differential interference contrast microscopy||Uses the difference in distances that the transmitted light travels after passing through a sample to generate color or brightness contrast for 3D observation||Colorless transparent samples, living cells|
|Modulation contrast (relief contrast) microscopy||Converts the difference in heights of a sample to brightness contrast for 3D observation||Cells in plastic containers|
|Fluorescence microscopy||Stains a sample with a fluorescent compound or fluorescent protein such as GFP to observe the part that expresses fluorescence||Cells and tissues dyed or labeled with a fluorescent dye, living organisms that exhibit intrinsic fluorescence|
|Reflected light microscopy||Uses reflected light to observe samples that do not pass light||Metals|
|Dispersion staining microscopy||Immerses a sample in index oil and uses transmitted light scattered in the oil for observation||Detection of asbestos|