Abstract: The present invention relates to an apparatus for the optical analysis of a sample, also referred to as microscope, which is configured for an optical analysis process having high resolution for the detection of fluorescent molecules. The apparatus and the process applied when using the apparatus are configured for excitation light generated by an excitation light source to be directed onto a sample and the light emitted by the probe is detected. The apparatus and the process are characterized in that the excitation light is synchronized with the detection. The apparatus is characterized in that it has a polarization device which is configured to modulate the polarization of the excitation light with a modulation signal, wherein the modulation signal has or consists of at least one frequency, in particular a pre-determined frequency or several pre-determined superimposed frequencies, or the modulation signal consists of a sequence of signals that has no repetition.