Quantitative phase imaging with programmable illumination

Taewoo Kim, Chris Edwards, Lynford L. Goddard, Gabriel Popescu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Even with the recent rapid advances in the field of microscopy, non-laser light sources used for light microscopy have not been developing significantly. Most current optical microscopy systems use halogen bulbs as their light sources to provide a white-light illumination. Due to the confined shapes and finite filament size of the bulbs, little room is available for modification in the light source, which prevents further advances in microscopy. By contrast, commercial projectors provide a high power output that is comparable to the halogen lamps while allowing for great flexibility in patterning the illumination. In addition to their high brightness, the illumination can be patterned to have arbitrary spatial and spectral distributions. Therefore, commercial projectors can be adopted as a flexible light source to an optical microscope by careful alignment to the existing optical path. In this study, we employed a commercial projector source to a quantitative phase imaging system called spatial light interference microscopy (SLIM), which is an outside module for an existing phase contrast (PC) microscope. By replacing the ring illumination of PC with a ring-shaped pattern projected onto the condenser plane, we were able to recover the same result as the original SLIM. Furthermore, the ring illumination is replaced with multiple dots aligned along the same ring to minimize the overlap between the scattered and unscattered fields. This new method minimizes the halo artifact of the imaging system, which allows for a halo-free high-resolution quantitative phase microscopy system.

Original languageEnglish (US)
Title of host publicationQuantitative Phase Imaging
EditorsYongKeun Park, Gabriel Popescu
ISBN (Electronic)9781628414264
StatePublished - 2015
Event1st Conference on Quantitative Phase Imaging, QPI 2015 - San Francisco, United States
Duration: Feb 7 2015Feb 10 2015

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


Other1st Conference on Quantitative Phase Imaging, QPI 2015
Country/TerritoryUnited States
CitySan Francisco


  • Interference
  • Microscopy
  • Optogenetics
  • Patterned illumination
  • Phase shifting
  • Quantitative phase imaging
  • SLIM

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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