the radiation fed by the radiation source module 2 into the scan module 3 to an infinite beam this is achieved with advantage in each case by using a single lens that has a focusing function achieved through displacement along the optical axis regulated by means of a central control unit not shown here whereby the distance between the collimator 12 13 and the respective end of the optical fiber is changeable the beam shaping unit which is explained in greater detail later generates from rotation symmetrical laser beam with gaussian profile as it is present after the beam combining mirrors 14 15 a line shaped beam which is no longer rotation symmetrical but has a cross section that is suitable for generating a field with rectangular illumination this illumination beam also said to be line shaped serves as the excitation radiation and is guided to a scanner 18 through a main dichroic beam splitter 17 and a zoom optic described later the main dichroic beam splitter is described in greater detail later suffice it to mention here that it has the function of separating the sample radiation returning from the microscope module 4 from the excitation radiation the scanner 18 deflects the line shaped beam along one or two axes after which it is bundled by a scanning.