Interference Based Linear Birefringence Measurements of Thermally-Induced Changes in Collagen

Duncan J. Maitland, Joseph T. Walsh

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations


Linear birefringence (LB) is a polarization-specific property of many semi-crystalline structures in tissue. Specifically, collagen, with its triple helix conformation, exhibits LB in its native state. Rat tail tendon (RU) was chosen for the LB experiments because it is >90% collagen and the collagen fiber alignment is nearly parallel with the RIT length'. This alignment results in RU exhibiting uniaxial characteristics such that two properly chosen optical axes display differing refractive indices (L\n= s1owfast) RU, which has an elliptical cross section, has its slow axis parallel to the tendons length and a fast axes along the tendon's cross section. Native RU has a refractive index difference of An=1.5x103. For a typical tendon thickness of 200 .tm, the phase shift, ö=n*d (d, diameter), is approximately equal to 300 nm (transmission measurement). Heating of RU results in a repeatable loss of ö. If monochromatic light is used the sample's output intensity is proportional to sin2(öir/) where ? is the wavelength of the light. Thus, given the native phase shift, the incident light's wavelength may be chosen such that the sample's loss of LB with heating is intensity-mapped on the sample's image.

Original languageEnglish (US)
Article number1342
Pages (from-to)304-308
Number of pages5
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Aug 17 1994
EventLaser-Tissue Interaction V; and Ultraviolet Radiation Hazards 1994 - Los Angeles, United States
Duration: Jan 23 1994Jan 29 1994

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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