Available Coating Technologies

In-house Technologies

Dielectric coatings consist of layers with different refractive indices. There are four major techniques used for dielectric coating: electron-beam deposition (E-beam), ion-assisted electron-beam (IAD), ion beam sputtering (IBS) and magnetron sputtering (MS). All of these processes are quite similar in their principle. They consist of evaporating some coating material and deposit it on the substrate. The difference lies in the deposition energy and method. Because of low energies involved when using electron-beam deposition, thin film contains bubbles and micropores like a sponge. These will eventually fill with water, which will change the refractive index of the coating and thus the properties of the optics. (This is known as “environmental shifting”). The presence of water also lowers the damage threshold of the optics: when exposed to an intense light, the water will tend to vaporise and dislodge off bits of the coating. Finally, even in the absence of water, inhomogeneities of coating layers decrease the theoretical damage threshold. The positive points about this technology is that it is cost effective, widespread and very versatile. The coating itself is also lightly flexible, which makes the optics more resistant to mechanical stress.

Here is our list of coating technologies available at Altechna:

• Electron beam evaporation

• Ion assisted deposition

• Ion beam sputtering

• Magnetron sputtering

Each technology is different and is used according to requirements of spectral sensitivity, damage threshold, hardness, surface quality etc.