A polarimeter is a device for determining the polarisation direction of the light or the rotation of an optically active substance. The physicist Francois Jean Dominique Arago made a discovery on quartz, which was very important for polarimetry. Arago cut a quartz crystal perpendicular to the crystal axis and saw the rotation of linearly polarised light on the cut quartz crystal.

The scientist Jean Baptiste Biot observed that the rotation of the polarisation axis also exists in certain liquids and gases of organic substances. His conviction: the optical activity is in some way related to the structure of the chemical compound.

The chemist Louis Pasteur continued Biot’s work by studying the optical activity of crystal forms with several salts of tartaric and racemic acid with a polarimeter. He realized that there are four different isomers: the counter-clockwise D (–) 17, the clockwise L (+) 16, the so-called racemic and one called meso-tartaric acid 18. The meso shape does not rotate the plane of polarized light. With this realization, he laid the foundation for the development of polarimetry.

A.KRÜSS polarimeters are ideal for analyzing optically active substances by determining their angle of rotation. They support all applications in industry, research, development and education.

Looking for refractometers? Browse our range here. Check out our You Tube channel for more product videos.