A fluorescence microscope lets excited light radiate the specimen and then sorts out the much weaker emitted light that makes up the image. The fluorescence microscope has a filter that only lets through radiation with the desired wavelength that matches the material that is fluorescing. The radiation collides with the atoms in the specimen and electrons are excited to a higher energy level. As these atoms relax to a lower level, they emit light. In order to become visible, this emitted light is separated from the much brighter excitation light in a second filter. The fluorescing areas can be observed in the microscope and shine out on a dark background with high contrast.
The images below are stained plant tissue that were captured using a fluorescence microscope by Fernan Federici for Cambridge University.
|Plant Fluorescing Proteins|
|Plant Cells Under the Microscope|