A dimming system (300) for dimming electromagnetic radiation intensity of a radiating unit, such as e.g., an optical system. The dimming system (300) is adjusted to provide a constant electromagnetic radiation intensity over the cross-section of the impinging electromagnetic radiation beam by providing at least two dimming units (320, 330) each having a spatially variable position-dependent dimming behavior, such that the degree of dimming for the whole cross-section can be chosen to be a fixed selectable dimming factor. The dimming units (320, 330) may be based on spatially variable position-dependent dimming devices based on transparent substrates having a coating with a position-dependent varying transmission/reflection coefficient, on spatially variable position-dependent diffusing devices or on polarizer devices.