Abstract: A polarimeter system and method for sensing optical rotation caused by otically active materials in a solution are disclosed. The polarimeter system (10) includes a light source (11) for emitting infrared light, a polarizer (14) operatively connected to intercept the infrared light to produce a polarized beam therefrom and means for directing the beam through a sample of optically active material (15), which rotates the light beam. A beam splitting prism (16) splits the rotated polarized beam into its horizontal and vertical components. Infrared light detectors (17a) and (17b) convert the horizontal and vertical components into electrical signals representative of the optical rotation caused by the sample solution. Shaping circuitry (26) conditions the electrical signals for use by analog or digital (28) networks, that present the optical rotation or its physical correlative factor. Feedback circuitry (36) may be used to vary the light source (11) intensity in response to the detected light signals.