Reflectance confocal microscopy of optical phantoms

A reflectance confocal scanning laser microscope (rCSLM) operating at 488-nm wavelength imaged three types of optical phantoms: (1) 100-nm-dia. polystyrene microspheres in gel at 2% volume fraction, (2) solid polyurethane phantoms (INO Biomimic(TM)), and (3) common reflectance standards (Spectralon(TM)). The noninvasive method measured the exponential decay of reflected signal as the focus (z(f)) moved deeper into the material. The two experimental values, the attenuation coefficient μ and the pre-exponential factor ρ, were mapped into the material optical scattering properties, the scattering coefficient μ(s) and the anisotropy of scattering g. Results show that μ(s) varies as 58, 8–24, and 130–200 cm(-1) for phantom types (1), (2) and (3), respectively. The g varies as 0.112, 0.53–0.67, and 0.003–0.26, respectively.