- Consider a plane wavefront of light that falls normally on a material such that only half of the wavefront enters the material, and the remaining half passes over the material with normal speed. Now, the part that travels through the material acquires path difference w.r.t. the other part of the wave that travels unhindered, will there be interference happening if these two parts are later converged to a point using a lens?
In the above diagram, I have illustrated what is written in the summery. So, if the thickness and refractive index of the material are chosen such that the part of the wave that travels through the slab acquires a path difference of λ/2 and at the right end if I keen another convex lens so as to converge the incoming parallel wavefronts to a point, will I be able to see a dark spot due to the fact that the rays will interfere destructively? Also, it would be really helpful if you could tell how is the wavefront of the light is going to look after it passes through the slab.