Effects of spatial coherence in diffraction phase microscopy

Chris Edwards, Basanta Bhaduri, Tan Nguyen, Benjamin G. Griffin, Hoa Pham, Taewoo Kim, Gabriel Popescu, Lynford L. Goddard

Research output: Contribution to journalArticle


Quantitative phase imaging systems using white light illumination can exhibit lower noise figures than laser-based systems. However, they can also suffer from object-dependent artifacts, such as halos, which prevent accurate reconstruction of the surface topography. In this work, we show that white light diffraction phase microscopy using a standard halogen lamp can produce accurate height maps of even the most challenging structures provided that there is proper spatial filtering at: 1) the condenser to ensure adequate spatial coherence and 2) the output Fourier plane to produce a uniform reference beam. We explain that these objectdependent artifacts are a high-pass filtering phenomenon, establish design guidelines to reduce the artifacts, and then apply these guidelines to eliminate the halo effect. Since a spatially incoherent source requires significant spatial filtering, the irradiance is lower and proportionally longer exposure times are needed. To circumvent this tradeoff, we demonstrate that a supercontinuum laser, due to its high radiance, can provide accurate measurements with reduced exposure times, allowing for fast dynamic measurements.

Original languageEnglish (US)
Pages (from-to)5133-5146
Number of pages14
JournalOptics Express
Issue number5
StatePublished - Mar 10 2014

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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    Edwards, C., Bhaduri, B., Nguyen, T., Griffin, B. G., Pham, H., Kim, T., Popescu, G., & Goddard, L. L. (2014). Effects of spatial coherence in diffraction phase microscopy. Optics Express, 22(5), 5133-5146. https://doi.org/10.1364/OE.22.005133