A
beam control system and method: The inventive
system includes, an arrangement for receiving a first beam of electromagnetic energy; measuring
wavefront aberrations in the first beam with a
wavefront sensor; and removing global tilt from the measured
wavefront aberrations to provide higher order aberrations for
beam control. In the illustrative embodiment, the invention uses a traditional (quad-
cell) Shack-Hartmann
wavefront sensor to measure wavefront aberrations. An
adaptive optics processor electronically removes the global tilt (angular
jitter) from this measurement leaving only the higher-order Zernike components. These higher-order aberrations are then applied to wavefront control elements, such as deformable mirrors or spatial light modulators that correct the tracker image and apply a conjugate
distortion to the wavefront of the outgoing HEL beam. A track error (angular
jitter) component is supplied by a separate fine track sensor. This
jitter error is then applied by the
adaptive optics processor to a fast steering mirror, which corrects jitter in the tracker image and applies a compensating
distortion to the LOS of the HEL beam.