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Suppression of speckles at high adaptive correction using speckle symmetry

Show simple item record Bloemhof, Eric E. 2007-06-29T15:05:21Z 2007-06-29T15:05:21Z 2006-08-13
dc.identifier.citation SPIE Annual Meeting, San Diego, California, August 13-18, 2006. en
dc.identifier.clearanceno 06-2704
dc.description.abstract Focal-plane speckles set important sensitivity limits on ground- or space-based imagers and coronagraphs that may be used to search for faint companions, perhaps ultimately including exoplanets, around stars. As speckles vary with atmospheric fluctuations or with drifting beamtrain aberrations, they contribute speckle noise proportional to their full amplitude. Schemes to suppress speckles are thus of great interest. At high adaptive correction, speckles organize into species, represented by algebraic terms in the expansion of the phase exponential, that have distinct spatial symmetry, even or odd, under spatial inversion. Filtering speckle patterns by symmetry may eliminate a disproportionate fraction of the speckle noise while blocking (only) half of the image signal from the off-axis companion being sought. The fraction of speckle power and hence of speckle noise in each term will vary with degree of correction, and so also will the net symmetry in the speckle pattern. en
dc.description.sponsorship NASA/JPL en
dc.format.extent 679903 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2006. en
dc.subject adaptive optics en
dc.subject speckles en
dc.subject atmospheric turbulence en
dc.title Suppression of speckles at high adaptive correction using speckle symmetry en
dc.type Preprint en

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