title: Closed loop adaptive optics for microscopy without a wavefront sensor.
abstract: A three-dimensional wide-field image of a small fluorescent bead contains more than enough information to accurately calculate the wavefront in the microscope objective back pupil plane using the phase retrieval technique. The phase-retrieved wavefront can then be used to set a deformable mirror to correct the point-spread function (PSF) of the microscope without the use of a wavefront sensor. This technique will be useful for aligning the deformable mirror in a widefield microscope with adaptive optics and could potentially be used to correct aberrations in samples where small fluorescent beads or other point sources are used as reference beacons. Another advantage is the high resolution of the retrieved wavefont as compared with current Shack-Hartmann wavefront sensors. Here we demonstrate effective correction of the PSF in 3 iterations. Starting from a severely aberrated system, we achieve a Strehl ratio of 0.78 and a greater than 10-fold increase in maximum intensity.
authors.affiliation: Faculty of Engineering, University of Georgia, Athens, GA 30602.
authors.forename: Peter
authors.initials: P
authors.lastname: Kner
authors.affiliation: Keck Advanced Microscopy Laboratory and Department of Biochemistry and Biophysics, University of California San Francisco, 600 16 St., San Francisco, CA 94158.
authors.forename: Lukman
authors.initials: L
authors.lastname: Winoto
authors.affiliation: Keck Advanced Microscopy Laboratory and Department of Biochemistry and Biophysics, University of California San Francisco, 600 16 St., San Francisco, CA 94158 ; Howard Hughes Medical Institute, University of California, San Francisco, CA 94143.
authors.forename: David A
authors.initials: DA
authors.lastname: Agard
authors.affiliation: Keck Advanced Microscopy Laboratory and Department of Biochemistry and Biophysics, University of California San Francisco, 600 16 St., San Francisco, CA 94158.
authors.forename: John W
authors.initials: JW
authors.lastname: Sedat
keywords: Adaptive Optics; Biomedical Imaging; Microscopy