Open AccessPartially coherent image formation in differential interference contrast (DIC) microscope
Author(s) -
Shalin B. Mehta,
Colin J. R. Sheppard
Publication year - 2008
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.019462
Subject(s) - differential interference contrast microscopy , optics , image formation , interference microscopy , microscope , coherence (philosophical gambling strategy) , interference (communication) , phase retrieval , spatial frequency , microscopy , materials science , contrast (vision) , phase (matter) , fourier transform , physics , image (mathematics) , computer science , artificial intelligence , computer network , channel (broadcasting) , quantum mechanics
Some different image formation models have been proposed for Nomarski's differential interference contrast (DIC) microscope. However, the nature of coherence of illumination in DIC, of key importance in image formation, remains to be elucidated. We present a partially coherent image formation model for DIC and demonstrate that DIC microscope images the coherent difference of shifted replicas of the specimen; but imaging of the each component is partially coherent. Partially coherent transfer functions are presented for various DIC configurations. Plots of these transfer functions and experimental images provide quantitative comparison among various DIC configurations and elucidate their imaging properties. Approximations for weak or slowly varying specimens are also given. These improved models should be of great value in designing phase retrieval algorithms for DIC.