Noninvasive Optical Polarimetric Glucose Sensing Using a True Phase Measurement Technique - Berkay Basagaoglu

About 16 million people in the United States have a form of diabetes, a metabolic disease manifested by inadequate control of glycemia. By maintaining a near normal (70–120 mg/dL) glucose concentration, diabetic patients can decrease the occurrence of complications. Therefore noninvasive glucose sensors are sought to provide continuous information on the current glucose levels. A novel method to detect glucose levels is through true phase optical polarimetry, in which the amount of rotation of polarized light by an optically active substance depends on several factors, including concentration. It is currently known that the concentration of glucose in the aqueous humor of the eye is a true reflection of the blood glucose level. Additive amplitude noise in the aqueous humor, due to biochemical and acids, presented a major problem in optical polarimetry. By inducing rotation of the linear polarization vector of the beam, in order to reduce the detection of change, amplitude variations, due to interactions with particulate matter were reduced significantly. In order to induce the rotation, a helium neon laser was passed through a linear polarizing sheet, a quarter wave plate (causes the light to be circularly polarized), and a rotating linear polarizer affixed to a motor (rotates the light at a specific frequency).

This article was interesting for me because they were able to noninvasively monitor an in vivo concentration through optics. 

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=142650