Evanescent field fluorescence microscopy is a very powerful imaging method for the investigation of interfacial issues in material science and biology. In waveguide evanescent field fluorescence microscopy, fluorescence dyes are excited within the evanescent field of a waveguide only: roughly within one hundred nanometers above the waveguide surface. This will allow imaging surface and interfacial issues of the waveguide and an adjacent material. Total Internal Reflection Fluorescence (TIRF) Microscopy is an example of an established evanescent field fluorescence microscopy. The advantages of this kind of microscopy is a very high axial resolution (in nanometer regime), but it is a very expensive method and not necessarily allows the substrate to be patterned. Waveguide Evanescent Field Fluorescence Microscopy (WEFF) is an inexpensive alternative, in the moment still with diffraction limited lateral resolution, but offers a lot of space above the specimen for additional instrumentation (e.g. patch clamp) and allows the waveguide as the substrate to be surface functionalized and/or patterned, both chemically and physically.In this method a laser beam couples into a waveguide, the basic component of WEFF, via a grating. The evanescent tail of the propagating beam in the waveguide will excite the fluorescence dyes. By utilizing an inverted fluorescence microscope and a DCC camera fluorescence images, fluorescence intensity maps and fluorescence kineticscan be captured, measured and saved to a computer. Our results show WEFF Microscopy is a very fast and easy imaging technique. We have investigated and imaged ultra-thin films of a few nanometer thicknesses, and also immobilized living cells. Besides quality control applications in ultra thin film technology, potential application for WEFF microscopy are drug screening in the form of kinetics of cell death, and cell death studies itself, e.g. how do cancer cells detach when they die. -
