Primate retina imaging with polarization-sensitive optical coherence tomography.

Polarization-sensitive optical coherence tomography (PSOCT) is applied to determine the depth-resolved polarization state of light backreflected from the eye. The birefringence of the retinal nerve fiber layer (RNFL) was observed and measured from PSOCT images recorded postmortem in a Rhesus monkey. An image-processing algorithm was developed to identify birefringent regions in acquired PSOCT retinal images and automatically determine the thickness of the RNFL. Values of the RNFL thickness determined from histology and PSOCT were compared. PSOCT may provide a new method to determine RNFL thickness and birefringence for glaucoma diagnostics.

Optical and thermal characterization of albumin protein solders.

The effect of temperature on the optical and thermal properties of pure and indocyanine green-doped albumin protein solders as a function of wavelength has been studied between 25 degrees C and 100 degrees C. An increase in the group refractive index by up to 4% and a decrease in absorption coefficient (approximately 800 nm) by up to 8%, after denaturing the solder specimens in a constant-temperature water bath at temperatures of 60-100 degrees C, were not significant. The reduced scattering coefficient, however, increased rapidly with temperature as the solder changed from being a highly nonscattering medium at room temperature to a highly scattering medium at temperatures close to 70 degrees C. The thermal conductivity, thermal diffusivity, and heat capacity increased by up to 30%, 15%, and 10%, respectively. Finally, the frequency factor and activation energy were measured to be 3.17 x 10(56) s(-1) and 3.79 x 10(5) J mol(-1), respectively, for liquid protein solders (25% bovine serum albumin) and 3.50 x 10(57) s(-1) and 3.85 x 10(5) J mol(-1), respectively, for solid protein solders (60% bovine serum albumin). Incorporation of dynamic optical and thermal properties into modeling studies of laser tissue interactions could have a significant influence on the determination of the expected zone of damage.