Excitation and Barrier Filters in Fluorescent Microscopy

The fluorescence tutorial explores how excitation and barrier filters can be interchanged to permit a wide spectrum of specific wavelengths to probe fluorescence samples. Detailed instructions on how to operate the tutorial are given below the applet window.

There are two sliders that control the wavelengths passed by the excitation and barrier filters. These can be adjusted by using the mouse cursor to move them back and forth, changing the wavelength. The bandwidth slider controls the width the band of wavelengths passed by the excitation filter, and has a range from 1 percent to 15 percent. Alternatively, you can select from pre-arranged filter combinations (used by Olympus microscopes in their filter cubes) by changing the cube code in the pull-down menu. Excitation and Barrier bandwidths for each filter cube combination are given to the right of the pull-down menu. There are some combinations of wavelengths selections for the barrier and excitation filters that do not allow any light to pass through into the observation tube.