Inclusion characterization in a scattering slab with time-resolved transmittance measurements: perturbation analysis

A procedure for the time-domain optical characterization of an inclusion in a scattering slab is investigated theoretically and experimentally. The me thod relies on the measurement of a contrast function, Which is defined as the time-dependent relative change in the transmitted signal resulting from the presence of the inclusion. Analytical expressions for the contrast fun ctions of absorptive and diffusive inclusions are obtained through a pertur bation solution of the diffusion equation This procedure is used successful ly to determine the optical properties of absorptive, diffusive, and mixed inclusions located at midplane in a scattering slab by use of time-resolved transmittance measurements. (C) 2000 Optical Society of America OCIS codes : 100.1830, 110.7050, 170.3010, 170.3660, 170.3830, 170.3880, 170.5280, 170 .6920, 170.7050, 290.1990,290.7050.