Abstract
A novel heterodyne polarimeter is designed to measure the concentration of chiral media. Optical common-path for the interference of the TE and TM waves, after a polarizer, is set up in our system to reduce noises from the environment. A phase-variable waveplate is placed behind the sample to enhance the phase signal change of rotation of polarization introduced by the sample itself. This enhancement can be excess two orders in amplitude when the retardation of the phase-variable plate is set close to 180 degree. With this polarimeter, the enhancement is -57.853 ~ -60.091 when the phase retardation of the phase-variable waveplate is 177.307 degree and considering the error of orientation angle. After calculating, the measurement of optical rotation angle of glucose solution with high resolution of 6.16×10-4 ~ 6.40×10-4 degree experimentally can be achieved, corresponding to concentration resolution of 13.48 ~ 14.00 mg/dl. We expect that, by further improvement, it can be applied in noninvasive blood glucose concentration monitoring for diabetics in the future.