Regular papers

Single scattering detection in turbid media using single-phase structured illumination filtering

Department of Physics, Division of Combustion Physics, Lund University, Sweden

^* edouard.berrocal@forbrf.lth.se

Received: 30 March 2012
Revised: 24 April 2012

Abstract

This work shows a unique possibility of visualizing the exponential intensity decay due to light extinction, when laser radiation propagates through a homogeneous scattering medium. This observation implies that the extracted intensity mostly originates from single scattering events. The filtering of this single light scattering intensity is performed by means of a single-phase structured illumination filtering approach. Results from numerical Monte Carlo simulation confirm the experimental findings for an extinction coefficient of µ_e = 0.36 mm⁻¹. This article demonstrates an original and reliable way of measuring the extinction coefficient of particulate turbid media based on side-scattering imaging. Such an approach has capabilities to replace the commonly used transmission measurement within the intermediate single-to-multiple scattering regime where the optical depth ranges between 1 < OD < 10. The originality of the presented approach is that only one image is used (instead of three images usually employed in structured illumination) and that no monitoring of the incident intensity is required, simplifying the experimental procedure and set-up. Applications of the technique has potential in probing challenging homogeneous scattering media, such as biomedical tissues, turbid emulsions, etc, in situations where dilution cannot be applied and where conventional transmission measurements fail.