Polarimeters are instruments used to measure the rotation of the plane of vibration in polarized light. Polarimetry of thin films and surfaces is called ellipsometry, which is used to provide information about layers that are thinner than the wavelength of the light itself, down to a single atomic layer or less. The most sensitive polarimeters are based on interferometers; while more conventional polarimeters use polarizing filters, wave plates or other devices.

Polariscope is an instrument for demonstrating the effects of polarised light. It consists of a polariser to obtain polarised light and an analyser to view the result. Polariscopes are a very useful, simple and inexpensive to make piece of gemological equipment. It is used to separate synthetic amethyst from genuine.

Polarization scrambler includes detecting, switching and controlling unit. The detecting unit is used to detect the output signal from the polarization scrambler coupled to the transmission line fiber. Switching unit is used for coupling one of the polarization scramblers to a transmission line fiber. Controlling unit is used for switching the polarization scrambler to another polarization scrambler using the switching unit when the output signal detected by the detection unit comprises a false output signal.

Polarization stabilizer is used for optimizing the performance of polarization dependent systems or devices.