title: Spiral interferometry.
abstract: We present a surprising modification of optical interferometry. A so-called spiral phase element in the beam path of a standard microscope results in an interferogram of phase samples, for which the interference fringes have the shape of spirals instead of closed contour lines as in traditional interferograms. This configuration overrides the basic problem of interferometry, i.e., that elevations and depressions cannot be distinguished. Therefore a complete sample profile can be reconstructed from a single exposure, promising, e.g., high-speed metrology with a single laser pulse. The method is easy to implement, it does not require a spatially separated reference beam, and it is optimally stable against environmental noise.
authors.affiliation: Division of Biomedical Physics, Innsbruck Medical University, Müllerstrasse 44, A-6020 Innsbruck, Austria.
authors.forename: Severin
authors.initials: S
authors.lastname: Fürhapter
authors.forename: Alexander
authors.initials: A
authors.lastname: Jesacher
authors.forename: Stefan
authors.initials: S
authors.lastname: Bernet
authors.forename: Monika
authors.initials: M
authors.lastname: Ritsch-Marte