University of St Andrews
School of Physics and Astronomy
12. Michelson interferometer and thin-film interference
Return to the First Year Waves and Optics Home
Page
Associated tutorial questions (St Andrews only)
- The Michelson Interferometer and its use in precision length measurements
- As one mirror is moved we can count how many fringes we see, and get the distance moved.
- We could also note how many fringes we see in a given time. We find this is the same as the Doppler shift of one wave off the moving mirror, and the whole experiment looked at using the idea of beats. We listen to the Doppler shift of light off a mirror moving at a few millimetres per minute in the lecture.
Next we look at other examples of two beam interference, including
- Anti-reflection coatings on spectacles or camera lenses
- Thin-film interference in soap or oil films
- two-beam interference off the pits and lands of a CD player
Note that your first year lab practical also looks at two-beam interference, this time in "Newton's Rings", which are the interference fringes formed by light reflected from either side of a thin air gap between a convex lens and a flat microscope slide.
Similar material to that presented in the lectures is available at:-
- Halliday, Resnick, & Walker - Chapters on:- Interference
Associated tutorial questions (St Andrews only)
Return to Waves and Optics Home Page
Created by, and copyright of, Bruce Sinclair, University of St Andrews; last modified 18/09/01