Filter Wheel

The light source for the fluorescence microscope often produces a wide spectrum of light, and an excitation filter can be used to limit the illumination light to a specific wavelength range appropriate for the sample. An emission filter is useful for blocking any light outside of the range of the emitted wavelength, thus improving the signal to noise ratio of the acquired image. This animation illustrates the light path in an upright microscope. Using a filter wheel, as shown in the animation, allows for rapid imaging of two different fluorophores.