Question

Polarization Microscopy.

See question below

polarised with a polariser in the analyser polarised in the horizontal direction. When one birefringent sample between the polarisers, the colour observed is green (wavelength of about 500 nm). Knowing that the material has a birefringence of n Suppose vertical direction and an now that you have a white light source inserts a -0.01, make an estimation of the minimum thickness of the plate

The answer is:

" Phase shift of pi, resulting in a thickness of 25 microns".

Can someone explain why the phase shift of pi?

Answer 1

A phase shift of Pi occurs because, upon inserting a birefringent sample, the incident ray splits into two peripheral rays with varying velocities. An inversion takes place due to a difference of speeds and therefore results in a shift of 180 degrees(Pi).