title: Diffraction grating three-beam interferometry without self-imaging regime contrast modulations.
abstract: Achromatic grating shearing interferometry method for wave front sensing is developed. Two Fresnel diffraction patterns formed by grating three lowest diffraction orders are recorded. The beam-splitter grating is displaced laterally by half its period between exposures. Calculating the sum of two patterns results in a two-beam interferogram free of inherent light propagation direction and observation plane contrast modulations imposed by the self-imaging phenomenon (Talbot effect). Single-frame automatic fringe pattern processing provides the interferogram phase distribution. The technique enables continuous shear variations suitable for dynamic range sensing. Experimental works corroborate enhanced capabilities of the proposed approach.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Patorski
authors.forename: Maciej
authors.initials: M
authors.lastname: Trusiak
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Pokorski