title: Active cophasing and aligning testbed with segmented mirrors.
abstract: An active segmented cophasing imaging testbed with a high accurate optical adjustment and control in nanoscale is set up. A two-dimensional dispersed fringe analysis method is used to calculate the piston error between the adjacent segments. Segments alignment of tip-tilt is fulfilled by overlapping diffraction pattern centroids of the individual segment on the focal plane. The cophasing errors are corrected by sensitive micro-displacement actuators under a computer closed-loop control. A FISBA interferometer is introduced to evaluate that a final total residual surface error of about 0.08λ RMS and the residual piston error of 0.026λ RMS are achieved (λ = 633 nm).
authors.affiliation: Department of Optoelectronic Engineering, Beijing Institute of Technology, Haidian District, Beijing, China. zwrei@bit.edu.cn
authors.forename: Weirui
authors.initials: W
authors.lastname: Zhao
authors.forename: Genrui
authors.initials: G
authors.lastname: Cao
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D007909:Lenses; D012031:Refractometry / Q000295:instrumentation*