A wavefront correction system was produced using a phase conjugating method
based on a point diffraction interferometer, or Zernike cell. This has the
main advantage that no separate reference beam is required. The PDI was co
nstructed using an optically addressed liquid crystal spatial light modulat
or, which means that the system is also relatively easy to align, and insen
sitive to tip/tilt errors, We demonstrate phase correction of induced high
spatial frequency aberrations, and show wavefront correction leading to a 3
x improvement in Strehl ratio. We also discuss the utility of the spatial
light modulator as a common-path point diffraction interferometer (C) 2001
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