A modulation device for use in a charged particle lithography system for patterning a plurality of charged particle beamlets in accordance with a pattern, the beamlets defining a column, the modulation device serving to modulate the beamlets to prevent one or more of the beamlets from reaching the target surface or allow one or more of the beamlets to reach the target surface, by deflecting or not deflecting the beamlets, the modulation device comprising: a plurality of apertures arranged in arrays for letting the beamlets pass through the modulation device and a plurality of modulators associated with the plurality of apertures, each modulator being provided with electrodes (32, 34) extending on opposing sides of an associated aperture for generating an electric field across the aperture; and a plurality of light sensitive elements arranged in arrays, for receiving modulated light beams and converting the light beams into electric signals for actuating the modulators; wherein a surface area of the modulation device is subdivided into a plurality of alternating beam areas and non-beam areas, the modulators being located in the beam areas, and the light sensitive elements being located in the non-beam areas, wherein the light sensitive elements in the non-beam areas are communicatively coupled to the modulators in an adjacent beam area, characterised in that the beam area is an elongated beam area comprising a two-dimensional array of apertures and associated modulators, wherein the non-beam area comprises an optical interface area in which the light sensitive elements are placed, and a power interface area for accommodating a power arrangement for suitably powering the light sensitive elements within the optical interface area, the power interface area being located alongside a long side of the elongated beam area and extending in a direction substantially parallel thereto. a plurality of apertures arranged in arrays for letting the beamlets pass through the modulation device and a plurality of modulators associated with the plurality of apertures, each modulator being provided with electrodes (32, 34) extending on opposing sides of an associated aperture for generating an electric field across the aperture; and a plurality of light sensitive elements arranged in arrays, for receiving modulated light beams and converting the light beams into electric signals for actuating the modulators; wherein a surface area of the modulation device is subdivided into a plurality of alternating beam areas and non-beam areas, the modulators being located in the beam areas, and the light sensitive elements being located in the non-beam areas, wherein the light sensitive elements in the non-beam areas are communicatively coupled to the modulators in an adjacent beam area, characterised in that the beam area is an elongated beam area comprising a two-dimensional array of apertures and associated modulators, wherein the non-beam area comprises an optical interface area in which the light sensitive elements are placed, and a power interface area for accommodating a power arrangement for suitably powering the light sensitive elements within the optical interface area, the power interface area being located alongside a long side of the elongated beam area and extending in a direction substantially parallel thereto.