CIRCULAR BIREFRINGENCE REFRACTOMETER: METHOD AND APPARATUS FOR MEASURING OPTICAL ACTIVITY

摘要

A system and method for detection and measurement of circular birefringences in materials, such as optically active (chiral) liquids and materials that exhibit the Faraday effect. The method and apparatus permit the detection of optical activities via the difference in the directions of propagation the left- and the right- circularly polarized light (components). A beam of light is directed at an interface formed by the optically active medium and another medium such that a difference in the angles of refraction and/or reflection and/or diffraction between the left- and the right-circularly polarized components of the light beam can be detected. The difference in the propagation directions between the two circularly polarized light components is measured on a position sensitive detector and/or is detected as an intensity difference. The circular birefringence in isotropic liquids is a measure of their optical purity (enantiomeric excess) and hence the invention presents a method and apparatus to measure chirality. The invention is thus related to optical rotation (polarimetric) measurements, but has the advantage that it does not depend on path-length traversed through the sample.