ECE532 Biomedical Optics © 1998 Steven L. Jacques, Scott A. Prahl Oregon Graduate Institute

Optical Properties

LECTURE:

• Absorption
  • Some biological chromophores
  • Definition and units of absorption coefficient µ_a [cm^-1]
  • Example: bilirubin
  • Absorption spectra for biological tissues
  
  
• Scattering
  • Some biological scatterers
  • Definition and units of scattering coefficient µ_s [cm^-1]
  • Definition of anisotropy g [dimensionless]
    • Scattering functions
    • Isotropic scattering function
    • Henyey-Greenstein scattering function
  • Reduced scattering coefficient µ_s' = µ_s(1 - g) [cm^-1]
  • Mie theory model for scattering
    • Brief overview of Mie theory math
    • Example calculation of angular scattering pattern
    • Example calculation of anisotropy
    • Example calculation of scattering cross section and coefficient
    • Scattering versus wavelength for 3 particle sizes
  • Mie scattering from cellular structure of soft tissues
  • Mie scattering from collagen fibers of dermis
  
  
• Summary
  
  

LAB:

• Goniometry of Mie scattering of polarized light by polystyrene spheres.
• Scattering coefficient of polystyrene spheres in water versus in syrup.
• Total diffuse reflectance to measure absorption coefficient: paper, ink added to milk.