Optical time-of-flight spectroscopy for highly scattering materials measurements

The paper presents benefits of optical time-of-flight spectroscopy for highly scattering materials to determine their basic optical properties (i.e. absorption coefficient, scattering coefficient, anisotropy factor and refractive index). The measurement techniques and methods of measured data analysis are presented too. The measurements were conducted for paper samples, technological liquids from paper mills and aqueous milk solutions. Picosecond semiconductor pulse lasers and fast light detectors (a streak camera and an avalanche photodiode working in Geiger mode) were used. It was shown that systems using these detectors and sources could provide measurement results that are very difficult or impossible to obtain by other measurement techniques.