Optical heterodyne-based method and apparatus for determining the concentration of optically active substances

摘要

In a method for determining concentration of an optically active substance in a medium, a laser beam with two eigen modes of two different temporal frequencies and two orthogonal linear polarized states is generated and passed through the medium. Then, the laser beam that exits the medium is passed through an analyzing polarizer so as to generate an optical heterodyne of the orthogonal linear polarized states. The amplitude of the optical heterodyne from the analyzing polarizer is detected, and the detected amplitude of the optical heterodyne is converted into the concentration of the optically active substance in the medium. An optical heterodyne-based apparatus for performing the above method is also disclosed. The method and apparatus are suitable for noninvasive in vivo glucose, monitoring of the aqueous humor in an eye of an animal.