A device used to change the nature of polarized light for analysis. It consists of a crystal of potassium, hydrogen, and phosphorus with a fine grid of gold electrodes on its surface. Depending on the voltage applied to the electrodes, light polarized in one direction can be arranged to emerge from the device 90° or 180° out of phase with the light polarized at right angles to it. The Pockels cell then acts as a quarter-wave plate or a half-wave plate respectively (see wave plate). It is named after the German physicist Friedrich Karl Alwin Pockels (1865–1913). Pockels cells are used in some polarimeters and spectropolarimeters.
Subjects: Chemistry — Astronomy and Astrophysics.