polariscope

An instrument for ascertaining, measuring, or exhibiting the properties of polarized light or for studying the interactions of polarized light with optically transparent media.

An optical instrument, various forms of which have been contrived, for exhibiting the polarization of light, or for examining substances in polarized light.

An instrument consisting essentially of a polarizer and an analyzer, used for polarizing light, and analyzing its properties.

a polarimeter

an optical device used to measure the rotation of the plane of vibration of polarized light