In the classical adaptive optics loop implementation the SID4 wavefront sensor is placed on the parallel (extraction) beamline and a beam reducer-telescope is used to adjust the laser size to the SID4 aperture and relay-image the deformable mirror plane to the SID4 sensor plane. The OASys software automatically performs the calibration of the deformable mirror by measuring the influence function of each actuator and runs the adaptive optics loop to converge to the desired wavefront.
The classical configuration gives great improvement of the laser focal spot quality but does not take in account the aberrations of the last focusing optics and the beam-reduction system in the extraction beamline. To master the correction of the full laser chain Phasics proposes the advanced configuration.