Portable, large-bandwidth time-resolved system for diffuse optical spectroscopy

We report the development of a compact time-resolved system for the measurement of the optical properties of highly scattering media over a bandwidth of 600-1000 nm. The instrument is based on a fiber laser generating supercontinuum radiation, that is spectrally dispersed and sequentially used to illuminate the sample. A single photon avalanche photo-diode in combination with time correlated single-photon counting is used to recover the time-dispersion curve at each wavelength, both fitted by the diffusion equation. Transmittance measurements performed on calibrated epoxy phantoms and in-vivo on female breast are presented, showing good agreement with previous reports. (C) 2007 Optical Society of America.