Polarization-sensitive optical coherence tomography provides high-resolution cross-sectional characterization of birefringence in turbid media. Weakly birefringent biological tissues such as the retinal nerve fiber layer (RNFL) require advanced speckle noise reduction for high-sensitivity measurement of form birefringence. We present a novel method for high-sensitivity birefringence quantification by using enhanced polarization-sensitive optical coherence tomography (EPS-OCT) and introduce the polarimetric signal-to-noise ratio, a mathematical tool for analyzing speckle noise in polarimetry. Multiple incident polarization states and nonlinear fitting of normalized Stokes vectors allow determination of retardation with ±1° uncertainty with invariance to unknown unitary polarization transformations. Results from a weakly birefringent turbid film and in vivo primate RNFL are presented. In addition, we discuss the potential of EPS-OCT for noninvasive quantification of intracellular filamentous nanostructures, such as neurotubules in the RNFL that are lost during the progression of glaucoma.
© 2005 Optical Society of America
(030.6140) Coherence and statistical optics : Speckle
(170.4470) Medical optics and biotechnology : Ophthalmology
(170.4500) Medical optics and biotechnology : Optical coherence tomography
(260.1440) Physical optics : Birefringence
(260.5430) Physical optics : Polarization
Nate J. Kemp, Jesung Park, Haitham N. Zaatari, H. Grady Rylander, and Thomas E. Milner, "High-sensitivity determination of birefringence in turbid media with enhanced polarization-sensitive optical coherence tomography," J. Opt. Soc. Am. A 22, 552-560 (2005)