Microdegree azimuth polarimeter using optical heterodyne detection

We have developed a highly accurate azimuth polarimeter using an optical heterodyne technique with a single-mode laser diode as a light source. Its minimum detectable rotation angle is 0.198 μdeg √W/Hz; i.e., it is inversely proportional to the square root of the laser power. Using a glass cell of 1-mm optical path length, we have also successfully observed the optical rotatory power of an aqueous glucose solution whose density is close to that of glucose in human blood.