title: High-visibility interferometric measurement of the diffraction phase.
abstract: We obtain the absolute phase in Fresnel diffraction for Gaussian beams by using a modified polarization Sagnac interferometer in which counterpropagating paths are spatially separated and labeled according to polarization. By erasing the polarization "which-path" information with an analyzing polarizer situated after the modified interferometer, we are able to regain interference and to precisely control the relative intensities of the diffracted and the reference beams. The resulting optimized visibility allows for a precise phase determination. This setup is very stable, requiring no active elements.
authors.affiliation: Department of Physics and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. salva@vt.edu
authors.forename: Salvador
authors.initials: S
authors.lastname: Barraza-Lopez
authors.forename: Daniel F V
authors.initials: DF
authors.lastname: James
authors.forename: Paul G
authors.initials: PG
authors.lastname: Kwiat
mesh_terms: D000465:Algorithms; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008857:Microscopy, Interference / Q000295:instrumentation / Q000379:methods*; D008859:Microscopy, Polarization / Q000295:instrumentation / Q000379:methods*; D044367:Phase Transition; D012031:Refractometry / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity