Polarimeter

A polarimeter is a polarimetry device used to measure the rotation of the plane of polarization of linearly polarized light by optically active substances. Some chemical substances are optically active, and polarized (unidirectional) light rotates either to the left (counterclockwise) or to the right (clockwise) as it passes through these substances. The amount by which the light is rotated is called the angle of rotation. The direction (clockwise or counterclockwise) and the amount of rotation provide information about the chiral properties of the sample, e.g., the relative concentration of enantiomers present in the sample.