Aperture effects in a scattering medium : A monte carlo phase space study of confocal imaging

Abstract

A study is carried out to understand better the spatial and angular/frequency dynamics of light scattered from a scattering medium at different planes of observations, with and without the presence of aperture(s). Several types of aperture such as circular, halfcircular and annular aperture are considered. The investigation is done within the context of a reflectance mode confocal microscope based on a 4-f optical system. A Monte Carlo simulation method to describe the focusing and propagation of light in a turbid medium is adopted. A new mechanism based on direction cosines is introduced to simulate photon propagation through different planes within the microscope system. The spatial distribution, spatial frequency distribution and phase space profile from such photonic simulations are observed and discussed. Statistics of the number of scattering events in different circumstances under different types of aperture are also discussed.