title: Spiral phase contrast imaging in microscopy.
abstract: We demonstrate an optical method for edge contrast enhancement in light microscopy. The method is based on holographic Fourier plane filtering of the microscopic image with a spiral phase element (also called vortex phase or helical phase filter) displayed as an off-axis hologram at a computer controlled high resolution spatial light modulator (SLM) in the optical imaging pathway. The phase hologram imprints a helical phase term of the form exp(i phi) on the diffracted light field in its Fourier plane. In the image plane, this results in a strong and isotropic edge contrast enhancement for both amplitude and phase objects.
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