Imaging with photoelastic modulators

Shane Nichols, John Freudenthal, Oriol Arteaga, Bart Kahr

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


Photoelastic modulators (PEMs) are among the most robust and precise polarization modulation devices, but the high frequency free-running nature of PEMs challenges their incorporation into relatively slow CCD and CMOS imaging systems. Current methods to make PEMs compatible with imaging suffer from low light throughput or use high cost intensified CCDs. They are not ideal for some analyses (microscopy, reflectivity, fluorescence, etc.), and likely cannot be extended to polarimeters with more than two PEMs. We propose to modulate the light source with a square wave derived from particular linear combinations of the elementary PEM frequencies and phases. The real-time synthesis of the square waves can be achieved using a field programmable gate array (FPGA). Here we describe the operating principle.

Original languageEnglish (US)
Title of host publicationPolarization
Subtitle of host publicationMeasurement, Analysis, and Remote Sensing XI
ISBN (Print)9781628410365
StatePublished - 2014
EventPolarization: Measurement, Analysis, and Remote Sensing XI - Baltimore, MD, United States
Duration: May 5 2014May 6 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherPolarization: Measurement, Analysis, and Remote Sensing XI
Country/TerritoryUnited States
CityBaltimore, MD


  • Ellipsometry
  • FPGA
  • Imaging
  • Microscopy
  • Mueller matrix
  • Photoelastic modulator
  • Polarimetry

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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