The performance of an adaptive optical system is strongly dependent upon correctly measuring the wavefkont of the arriving light. The most common wavefront measurement techniques used to date are the shearing interferometer and the Shack-Hartmann sensor. Shack-Hartmann sensors rely on the use of lenslet arrays to sample the aperture appropriately.These have traditionally been constructed using MLM or step and repeat technology, and more recently with binary optics technology. DiEractive optics fabrication methodology can be used to remove some of the limitations of the previous technologies and can allow for lowvast production of sophisticated elements.We have investigated several different specialized wavefront sensor configurations using both Shack-Hartmann and shearing interferometer principles. We have taken advantage of the arbitrary nature of these elements to match pupil shapes of detector and telescope aperture and to introduce magnification between the lenslet array and the detector. W e have fabricated elements that facilitate matching the sampling to the current atmospheric conditions. The sensors were designed using a far-field diffraction model and a photolithography layout program. They were fabricated using photolithography and R E etching. Several different designs will be presented with some experimental results from a small-scale adaptive optics brass-board.

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Scaling laser systems to large sizes for power beaming and other applications can sometimes be simplified by combining a number of smaller lasers. However, to fully utilize this scaling, coherent beam combination is necessary. This requires measuring and controlling each beam's pointing and phase relative to adjacent beams using an adaptive optical system.We have built a sub-scale brass-board to evaluate various methods for beam-combining. It includes a segmented adaptive optic and several different specialized wavefront sensors that are fabricated using diffractive optics methods. We have evaluated a number of different phasing algorithms, including hierarchical and matrix methods, and have demonstrated phasing of several elements. The system is currently extended to a large number ofisegments to evaluate various scaling Keywords: adaptive optic, wavefront sensor, coherent beam combiningmethodologies.r :

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