This optical set-up, designed and built inside our group, is used to visualize flow experiments in micro-models of various sizes and types. The main advantage of this set-up is that it can visualize micro-models bigger then 5x5 mm, maximum field of view, at a resolution of 2.8μm/pixel.
The set-up consists of four cameras, with resolution of 5 megapixels each, located on four sides of a box containing 3 beam splitters. The beam splitters to split the image into 2 identical ones, leading up to a total of 4 identical images, each one recorded by a camera. The incoming beam to the beam splitters has been magnified by an macro lens.
The illumination of the micromodels and the diversion of the light beam towards the objective lens depend on the type of micromodel and its refractivity. Transparent micro-models, such as PDMS, are placed between the light source and a prism that redirects the beam to the lens. On the other hand for opaque micro-models, like Silicon-Pyrex, a beam splitter sits the between micro-model and the light source, which will divert the reflected beam to the lens.
The micro-model is placed between two pressure transducers, one in each side of the micromodel. In this way it is possible to measure, set and control the pressure between the two sides of the micromodel.