Open AccessLifting degeneracy in holographic characterization of colloidal particles using multi-color imaging
Author(s) -
David B. Ruffner,
Fook Chiong Cheong,
Jaroslaw M. Blusewicz,
Laura A. Philips
Publication year - 2018
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.26.013239
Subject(s) - holography , optics , characterization (materials science) , diffraction , microscopy , digital holographic microscopy , degeneracy (biology) , particle (ecology) , wavelength , materials science , physics , bioinformatics , biology , oceanography , geology
Micrometer sized particles can be accurately characterized using holographic video microscopy and Lorenz-Mie fitting. In this work, we explore some of the limitations in holographic microscopy and introduce methods for increasing the accuracy of this technique with the use of multiple wavelengths of laser illumination. Large high index particle holograms have near degenerate solutions that can confuse standard fitting algorithms. Using a model based on diffraction from a phase disk, we explain the source of these degeneracies. We introduce multiple color holography as an effective approach to distinguish between degenerate solutions and provide improved accuracy for the holographic analysis of sub-visible colloidal particles.