An optical arrangement and a related method for operating this optical arrangement are suggested, particularly in microscopes, for use as at least one of a main beam splitter and a beam combiner. One or more light beams can be coupled into the arrangement and at least one of the light beams that were coupled in can be coupled out again after having passed through the optical arrangement. In the path of the coupled in light beams at least one controllable microstructured element is provided, allowing to switch beam paths within the optical arrangement. This allows controlling or influencing the one or more light beams that are coupled out.