The present invention relates to a confocal laser scanning microscope (100) having an illumination device (1) that comprises a laser light source (41) that is configured to illuminate a sample (25), and a control application circuit (40) for the laser light source (1) which is configured to output a pulsed control application signal (48) in order to supply the laser light source (41), the control application circuit (40) being configured so that it determines both a pulse amplitude (A) and a pulse width (W) of at least one pulse of the pulsed control application signal (48) as a function of at least one input variable (S).