Scattering light rejection by confocal microscopy

Abstract

Multiple and single scattering of light is a regular phenomenon we often see around us. Single scattering occurrences caused by atmospheric density fluctuations are responsible for the blue-colored sky while the white appearance of clouds is caused by the diffuse re-emission of scattered sunlight. Not so well known is the fact that the relative opacity of skin tissues is due primarily to the presence of multiple scattering. The typical scattering mean-free path of the dermis is 10-100 μm so that light incident on a 1 mm sample is scattered at least 10 times prior to detection. The rejection of multiple scattered light can therefore render skin tissues transparent to imaging and vital information hidden beneath the tissue layers can be extracted. In this light, the capability of the confocal microscope to resolve objects into thin optical sections can be used to filter out scattered photons.
In this work, we compare the performance of confocal and conventional microscopes in non-invasive imaging. The effects of the density and the anisotropy of a simulated scattering medium on the effective confocal parameters: transverse resolution and image contrast, are likewise investigated.