The GATTAscope uses the TIRFM process (total internal reflection fluorescence microscopy). To achieve total reflection, the laser beam does not hit the sample to be examined orthogonally, but at a flat angle. Therefore, the laser beam does not penetrate deeply into the sample, but instead only stimulates fluorescence of the molecules on the surface. The resulting image has a much higher contrast than an image produced by classical fluorescence microscopy.
A radiation cage with mirror and lenses is moved vertically to set the critical angle required in the GATTAscope, so the beam does not go through the center of the lens but is deflected to the edge at a certain angle. Total reflection is achieved when the critical angle is reached exactly. Two Q-545 Q-Motion® precision linear drives take care of this job. Thanks to their piezoelectric inertia principle, they provide high nanometer-accurate position resolution, are compact and on top of that, inexpensive. Control is done by the E-870 PIShift driver electronics.