Retroreflective imaging system for optical labeling and detection of microorganisms

Mark H. Bergen, Jacqueline Nichols, Christopher M. Collier, Xian Jin, Balakrishnan Raja, Deborah J. Roberts, Paul Ruchhoeft, Richard C. Willson, Jonathan F. Holzman

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


A retroreflective imaging system for imaging microscopic targets over macroscopic sampling areas is introduced. Detection of microorganism-bound retroreflector (RR) targets across millimeter-scale samples is implemented according to retroreflection directionality, collimation, and contrast design characteristics. Retroreflection directionality is considered for corner-cube (CC) and spherical geometries. Spherical-RRs improve directionality and reliability. Retroreflection collimation is considered for spherical-RRs. Retroreflective images for micro-CC-RRs and micro-spherical-RRs with varying refractive indices show optimal results for high refractive index BaTiO3micro-spherical-RRs. A differential imaging technique improves retroreflection contrast by 35 dB. High refractive index micro-spherical-RRs and differential imaging, together, can detect microscopic RR targets across macroscopic areas.

Original languageEnglish (US)
Pages (from-to)3647-3655
Number of pages9
JournalApplied Optics
Issue number17
StatePublished - Jun 10 2014

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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