Does Fresnel reflection involves absorption of light?

[AlKindi]

When a ray interacts with a solid if the surface is polished reflection occurs. This is true even if the material absorbs at the specific wave lenght? In other words if the material absorbs at the specific λ, can occurs Fresnel reflection ? Or: Fresnel reflection has always all the same λs of the incident ray? Thanks a lot!

 

[Born2bwire]

Technically, you can have absorption without reflection but these are artificial constructs (Perfectly Matched Layer (PML)). In practice, any time you have absorption you are going to have a change in the impedance across the boundary which will give rise to some amount of reflection. On the other hand, you do not need absorption for reflection to occur. There are ways to reduce the net reflection off of a surface, like the treatments in an anechoic chamber. But these rely on trapping the wave and gradually absorbing it before it can reflect back out into the open.

 

[AlKindi]

Thanks a lot Born2bwire, you solve me a great doubt. So if I'm a spectroscopist I know that I can't obtain any information from the Fresnel reflection, but does the amount of Fresnel reflection varies if are involved absorption phenomena?