Abstract
In this study, we improved an optical common-path heterodyne polarimeter. We not only utilize the common-path setup to reduce noises from the environment, but also use the heterodyne technique to pick up signals with other frequencies. Furthermore, we replace with the old phase-variable waveplate with a Soleil-Babinet compensater(SBC) and design a sample transmission setup to automate our system. We control the phase retardation and orientation angle of the SBC with specialized software installed in the computer. And collocate the electromagnetic valve and peristalsis pump to transmit sample solutions. Therefore, We can steadily and precisely enhance the phase difference signal induced by the chiral media. After the improvement, the system demonstrated an enhancement of about 45. We use this improved polarimeter to measure the optical rotation angles of different concentrations of glucose solution with and without polystyrene respectively. After calculating, the resolutions of optical rotation angle of glucose solution with and without polystyrene are 2.23×10-4 and 8.93×10-5 degree respectively, the corresponding concentration of glucose resolution are 5.6 mg/dl、2.2 mg/dl. For detection limit, both two cases have the same value 15.6 mg/dl. We expect that, by further improvement for stability, it can be applied in noninvasive blood glucose concentration monitoring for diabetics in the future.