Wavelength Selection

In fluorescence microscopy, the excitation light is generally passed through a bandpass interference filter to select a specific band of wavelengths that are used to illuminate the fluorophore. Depending upon the filter characteristics and the light source, the amount of light available for excitation can vary by a wide margin. This interactive tutorial is designed to enable the visitor to choose between various ZEISS filter sets and common microscope illumination sources to determine the optimum combination for a specific application.

One of the most useful and cost-effective configurations to achieve wavelength selection in fluorescence microscopy involves placing a polychroic mirror in a standard fluorescence filter optical block and using separate filter wheels under computer control to rotate the proper excitation and emission filters into the optical pathway when necessary. This interactive tutorial examines wavelength switching with an aftermarket filter wheel coupled to an external metal halide lamphouse.

Temporal investigation of events in living cells requires the ability to capture successive images on a wide spectrum of timescales, often spanning the range of microseconds to minutes. The Sutter Lambda DG-4 device featured in this tutorial is a complete interference filter-based xenon-powered illumination system that exhibits switching speeds of less than 2 milliseconds.