Near-Infrared Scattering Effects of Mesoporous TiO2 Analyzed by Optical Coherence Tomography

Optical properties of mesoporous TiO2 scatters with average diameters of 20 nm, 150 nm, 300 nm, and 500 nm are measured by optical coherence tomography system at the wavelength of 853 nm. The scattering coefficient can be estimated by utilizing the extend Huygens Fresnel theory with consideration of single and multiple scattering effects, and the g factors are calculated based on the Mie scattering model. After fitting algorithm, by increasing the sizes of mesoporous TiO2 scatters from 20, 150, 300, to 500 nm, the scattering coefficient could also be extracted as from 13.5 +/- 0.6, 16.5 +/- 0.6, to 20.2 +/- 0.6 mm(-1), and then decreased to 18.5 +/- 0.6 mm(-1), which are accompanied with the enhancement of multiple-scattering contribution from 5%, 10%, to 40%, and then decreased to 20%, respectively.