What are some advantages and disadvantages of Michelson Interferometer?

1 Answer
Sep 16, 2017

Advantages: Simple, easy to create, very accurate when used correctly
Disadvantages: Hard to get accurate, 50% of the light can be reflected back to the source


A Michelson Interferometer is tool used for optical interferometry. Using a beamsplitter, a light source is reflected into two arms, where both light beams are then reflected back towards the beam splitter. The beam splitter then uses the superposition principle (for all linear systems, the net response at a given place and time caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually, https://en.wikipedia.org/wiki/Superposition_principle) to combine the amplitudes.

When this happens, an interference pattern occurs, and if it suits the purpose of the experiment it can directed to a type of camera or photoelectric detector. See picture below for a visual representation:

There are advantages to using a Michelson Interferometer. One of them is that it is very simple to set up, needing only a beam splitter, two mirrors, a light source and optionally a detector, which are all available in shops or online. Another advantage is that if it is set up correctly, the results are most precise, enough so that versions of Michelson Interferometers have been used to take recordings of the distance of stars and the cosmic microwave background

There are also disadvantages to using a Michelson Interferometer. One is that the simplest, and by extension cheapest version reflects 50% of light back to the source, reducing the reliability of measurements made. To get around this one can use cube-corner mirrors and the four-port desing, but that makes it more expensive.
Another disadvantage of the Michelson Interferometer is that to get accurate readings, especially for white light, can be quite difficult and requires precise control of the beam paths.

I hope I helped!