OPTICAL MODULATOR WITH BEAM-POINTING CORRECTION

摘要

An apparatus for providing a modulated pulsed radiation beam (20) has a radiation source (16) for providing a pulsed radiation beam (10) at a constant pulse repetition frequency and a number of beam intensity modulators (18a-18e). A beam-deflecting element (12) in the path of the pulsed radiation beam and rotatable about an axis redirects the pulsed radiation beam cyclically towards each of the plurality of beam intensity modulators in turn. A beam-recombining element rotatable about the axis in synchronization with the beam-deflecting element combines modulated light, from each of the beam intensity modulators in order to form the modulated pulsed radiation beam at the constant pulse repetition frequency. At least one beam-pointing correction apparatus optically conjugates the beam-deflecting element and the beam recombining element at least one rotational position about the axis.