title: Dynamic closed-loop system for focus tracking using a spatial light modulator and a deformable membrane mirror.
abstract: A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track defocus over a distance of up to 80 microm with an RMS precision of 57 nm. For demonstration purposes we concentrate on defocus, although in principle the method applies to any wavefront shape or aberration that can be successfully reproduced by the deformable membrane mirror and spatial light modulator, for example, spherical aberration.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Wright
authors.forename: Brett A
authors.initials: BA
authors.lastname: Patterson
authors.forename: Simon P
authors.initials: SP
authors.lastname: Poland
authors.forename: John M
authors.initials: JM
authors.lastname: Girkin
authors.forename: Graham M
authors.initials: GM
authors.lastname: Gibson
authors.forename: Miles J
authors.initials: MJ
authors.lastname: Padgett