Refractive Indicies

Berdi

So, I was in my Undergraduate Labs yesterday, using Newton's Rings to determine the Refractive index of water. I was just wondering, other than measuring the angles of incident and refracted beams, if there were many other methods to determine refractive index?

Andy Resnick

The most sensitive measurements, AFAIK, use total internal reflection (critical angle measurement).

For small homogeneous particles, the refractive index can be measured via scattering (Mie scattering), but the accuracy is not as good as TIR.

Vanadium 50

You might also look up "Brewster's Angle". This even lets you measure the index of refraction of opaque objects.

mgb_phys

You can use an interferometer to compare the distance a coherent wave goes in air (or ieally vacuum) with one going through an other medium and see how they add up - this is essentially what Newton's rings is doing.