Open AccessMeasuring the modulus of the spatial coherence function using an error tolerant phase shifting algorithm and a continuous lateral shearing interferometer
Author(s) -
Irina Harder,
Martin Eisner,
R. Völkel,
Sergej Rothau,
Johannes Schwider,
Peter Mario Schwider
Publication year - 2016
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.005087
Subject(s) - interferometry , optics , shearing interferometer , shearing (physics) , coherence (philosophical gambling strategy) , degree of coherence , white light interferometry , interference (communication) , algorithm , computer science , physics , astronomical interferometer , telecommunications , beam (structure) , channel (broadcasting) , quantum mechanics , thermodynamics
The modulus of the degree of coherence can be derived from interference patterns either by using fringes and next neighbour operations or by using several interferograms produced through phase shifting. Here the latter approach will be followed by using a lateral shearing interferometer exploiting a diffractive grating wedge providing a linearly progressive shear. Phase shifting methods offer pixel-oriented evaluations but suffer from instabilities and drifts which is the reason for the derivation of an error immune algorithm. This algorithm will use five π/2-steps of the reference phase also for the calculation of the modulus of the coherence function.