title: Holography-based wavefront sensing.
abstract: We describe a modal wavefront sensing technique of using multiplexed holographic optical elements (HOEs). The phase pattern of a set of aberrations is angle multiplexed in a HOE, and the correlated information is obtained with a position sensing detector. The recorded aberration pattern is based on an orthogonal basis set, the Zernike polynomials, and a spherical reference wave. We show that only two recorded holographic patterns for any particular aberration type are sufficient to allow interpolated readout of aberrations to lambda/50. In this paper, we demonstrate the capability of detecting errors between +/-2lambda PV for each orthogonal set at rates limited only by the speeds of the detection electronics, which could be up to 1 MHz. We show how we take advantage of the unavoidable intermodal and intramodal cross talks in determining the type, amplitude, and orientation of the wavefront aberrations.
authors.affiliation: Lockheed Martin Corp., Space Systems Co., O'ABDS B/201, 3251 Hanover Street, Palo Alto, California 94304, USA. fassil.ghebremichael@lmco.com
authors.forename: F
authors.initials: F
authors.lastname: Ghebremichael
authors.forename: Geoff P
authors.initials: GP
authors.lastname: Andersen
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Gurley