Liquid-crystal Hartmann wave-front scanner

The liquid-crystal wave-front scanner (LCWS) is a highly sensitive wave-fro nt sensor suited to the measurement of aberrations in optical systems and, more generally, of static wave fronts, and it is based on the Hartmann test . In the LOWS an incoming wave front is scanned sequentially by a programma ble moving aperture that is implemented by use of a liquid-crystal display. The position of the diffraction spot is recorded behind an observation len s with a CCD detector and provides an estimation of the local slopes in two orthogonal directions at the aperture position. The wave front is then rec onstructed from slope data by use of a least-squares method. Experiments ar e reported for nearly planar wave fronts as well as for strongly aberrated wave fronts, demonstrating both the large dynamic range and the great sensi tivity of the LOWS. The LOWS is compared with the Shack-Hartmann wave-front sensor in terms of dynamic range and sensitivity. (C) 2000 Optical Society of America OCIS codes: 010.7350, 120.5050, 230.6120.