The Sagnac interferometer was first used by Georges Sagnac in 1913 and the Sagnac effect named after him was thus demonstrated. You will find information on the basic principle of the experimental setup at that time, which is now also referred to as a passive Sagnac interferometer, on your worksheet.

In 1963 a more advanced version was introduced, known as the active Sagnac interferometer. You will find such an experimental setup in this ISE and in the Geogebra simulation.

A Sagnac interferometer is a very effective angular rate sensor, as you will find out in this experiment. It is used in aviation and shipping, but also in industry, in order to be able to precisely measure much faster rotation rates.

Attention: Audios can be played in this ISE. Therefore, check the speaker settings of your device. Turn it down a little first and adjust the volume if necessary.

Author: Hendrik Maas, Physics Didactics group, 2023

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