Types of interference structure

There are to types of distinguished refractive interference structures: refractive-type miltilayers and bragg-type multilayers,An example of a multi-layer structure is the peacock feather that consists of alternate layers of melamine and keranine as shown in figure 1 on page 18.

a)Refractive-type multilayers-These consist of a limited number of deposited layers with large differences in refractive index to render the stack of high reflection.

An example is the optically variable ink.