An optical company coats a glass lens (nglass=1.52) with a single layer of magnesium fluoride (nMgF2=1.38) to reduce reflections of green light (λ0=550nm in air). Light strikes the lens at 25∘ from the normal in air.
(a) Determine the angle that the light makes with the normal while it is inside the MgF2 layer.
(b) Calculate the minimum physical thickness of the MgF2 layer that will minimize reflection of the green light. Assume unpolarized light.
(a) Determine the internal angle in the MgF2 layer.
(b) Calculate the minimum coating thickness that minimizes reflection of λ0=550nm light.