Thin Film Interference:

1
Thin Film Interference
Reflection from soap film
2
?2
?
?1
?
?x
3
Maxima if n2 gt n1 ?? is due to sign change for
internal bounce
4
Newtons rings
Find the thickness of the air gap as function of
rm
R
rm
tm
5
Michelson Interferometer
6
Perfectly constructive interference
Phase change at internal reflection makes max
into min
7
Determination of the index of refraction of air
?X
8
We have two passes through the vacuum chamber of
length L
We cant pump down to vacuum, instead count
fringes as we pump and extrapolate