What are the characteristics of optical films

Let us introduce the characteristics of optical thin films. 

The surface is smooth, and the interface between the layers is geometrically divided; the refractive index of the layer can jump at the interface, but it is continuous in the layer; it can be a transparent medium , or it can be an absorbing medium; it can be homogeneous in the normal direction or non-uniform in the normal direction. The actual thin film is much more complex than the ideal thin film. This is because: during preparation, the optical and physical properties of the thin film deviate from the bulk material, and its surface and interface are rough, resulting in diffuse scattering of the light beam; interpenetration between the film layers forms a diffusion interface; due to the growth of the film layer , structure, stress and other reasons, the anisotropy of the film is formed; the film layer has a complex time effect. The above is the explanation of the optical films we use. Optical films are actually seen everywhere in daily life.