Holographic compensation of wavefront aberrations in optical systems

Holographic compensation of residual aberrations in an experimental optical system is investigated. A series of holographic corrector plates (HCP's) of a given subject lens are constructed for on-axis, monochromatic point sources only. A Hartmann mask is constructed and used to determine the relative effectiveness of the HCP to compensate for point sources that are positioned up to plus or minus 5 degrees off-axis. Although off-axis corrections by the lens/HCP system are more than adequate when compared with the lens alone, hologram diffraction efficiency and vignetting of the diffracted light at the entrance pupil of the lens greatly reduce the HCP effectiveness. To overcome these problems, phase-type holograms having a 40.0 percent diffraction efficiency and secondary HCP's placed directly against the subject lens are constructed. In addition, an HCP repositioning technique based on Moire fringe patterns is developed.