Question

No sloppy writing, please. I want to be able to see and understand each step. Thank you in advance! :)

A monochromatic red light at 640 nm is reflected as much as possible from a very thin film, but monochromatic green light at 480 nm doesn't really reflect from the film. The refractive index of the film material is 1.3, the light comes perpendicularly onto the film, and there is air on both sides of the film. What is the minimum film thickness?

result: 300 nm <minimum thickness <400 nm

Answer 1