The invention relates to a compensator
system adapted to compensate for the
angular dispersion of electromagnetic beams deflected by at least one acousto-optic deflector of an optical
system, wherein the
angular dispersion of each deflected beam is dependent on the
deflection angle obtained by the deflecting
acoustic frequency of the acousto-optic deflector, characterised in that the compensator
system comprises: - a first lens group for spatially separating the deflected beams of different
deflection angle and
angular dispersion by focusing the beams substantially into the focal plane, - a compensator element having a first surface and a second surface, and being arranged such that the first surface of the compensator element lies substantially in the focal plane of the first lens group, and the first and second surfaces of the compensator element have nominal radiuses R1 and R2 that together work as prisms with tilt angles beta and
prism opening angles alphap that vary with the distance from the
optical axis so as to compensate for the angular dispersion of the spatially separated deflected beams, - a second lens group arranged so as to substantially parallelise the different
wavelength components of each deflected beam exiting the compensator element while maintaining the
angular variation of the beams deflected at different acoustic frequencies. The invention further relates to method for compensating for the angular dispersion of electromagnetic beams deflected by at least one acousto-optic deflector of an optical system, wherein the angular dispersion of each deflected beam is dependent on the
deflection angle obtained by the deflecting
acoustic frequency, characterised by - spatially separating the deflected beams of different deflection angle and angular dispersion by focusing the beams via a first lens group substantially into the focal plane of the first lens group, - compensating for the angular dispersion of the spatially separated deflected beams in accordance with the angular dispersion of the given beam, - substantially parallelising the spectral components of each deflected beam while maintaining the
angular variation of the beams deflected at different acoustic frequencies.