Research and Development of a Differential Laser Polarimeter to Measure the Glucose Concentration in Turbid Media

Method of optical polarimetry is well known, but earlier it was mainly used to low scattering media. In this paper we consider the possibility of measuring the glucose concentration by detecting polarization of the backscattered laser light. As object of research a human finger have been chosen. The optimal parameters of the probing light were identified, degree of polarization of light scattered by human skin and model objects was registered. A laboratory model of a differential polarimeter, which allows to register the parameters of the polarized radiation scattered by human skin and glucose containing models, was developed. Using the developed polarimeter, model and full-scale experiments were carried out. In the model experiments we investigated the light backscattered by the following objects: a 20% solution of milk and a 50% suspension of human blood. During experiments it was shown, that the amount of optical rotation is also dependent on the angle of registration and, hence, photodetectors position in space is important. The ability of the developed sensor to noninvasively detect the concentration of glucose in the blood was demonstrated. However, its sensitivity to the structure of human skin and the individual characteristics of the organism was identified. This suggests that in order to achieve maximum accuracy it is necessary to carry out individual adjustment and calibration of measuring equipment.