SHEARING INTERFEROMETRY FOR LASER-GUIDE-STAR ATMOSPHERIC CORRECTION AT LARGE D R(0)/

Shearing interferometry offers a possible method to scale wave-front s ensors to the large number of subapertures that will be required for c orrection of the new generation of large 6-10-m-class telescopes at vi sible wavelengths. We discuss static shearing interferometers, which a re prototype wave-front sensors for use with laser guide stars at larg e values of D/r(0). The dc interferometers utilize low-noise detector array technology and can be implemented with a variety of shear length s to accommodate different atmospheric conditions. We discuss the opti cal design and the noise sensitivity of two versions of de interferome ter. Atmospheric tests of the interferometers for correcting a 500-sub aperture adaptive system are presented, including fringe data obtained with ultraviolet and visible laser stars and compensated ultraviolet images of Vega obtained at our test facility in San Diego.