Simulation of confocal microscopy through scattering media with and without time gating

An efficient and fast simulation technique is presented to calculate charac teristic features of confocal imaging through scattering media. The simulat ion can predict the time-resolved confocal response to pulsed illumination that allows optimizing of imaging contrast when time-gating techniques are applied. Modest computational effort is sufficient to obtain contrast predi ctions for arbitrary numerical aperture, focus depth, pinhole size, and sca ttering density, while the simulation accuracy is independent of scattering density and pinhole size. In the case of isotropic scattering, our results indicate that reflection-mode confocal imaging through scattering media is limited to mud approximate to 3.5 optical thicknesses for continuous-wave illumination. If time-gating is applied, imaging through scattering densiti es of mud approximate to 8 is theoretically possible. (C) 2001 Optical Soci ety of America.