The Fresnel triprism and the circular polarization of light

In 1822 Augustin Fresnel discovered the circular polarization of light with an experiment in which a plane polarized beam was resolved into its left- and right- circularly polarized components after refraction at slightly different angles at the interface between two different species of quartz that formed a composite prism, called the Fresnel triprism. Fresnel’s landmark experiment, once popular, remains today a very little known method for producing circularly polarized light