Optical Coatings

An optical coating is one or more thin layers of material deposited on an optical component which alters the way the optic interacts with light. The simplest example is a thin layer of metal, such as silver, deposited on to a glass substrate to make a mirror. Another common type of coating is a dielectric coating consisting of a single or multilayer structure which uses different refractive indices and thicknesses to manipulate the transmission and reflection of light by the optic. These are constructed from thin layers of materials such as magnesium fluoride, calcium fluoride, and various metal oxides, which are deposited onto the optical substrate. By careful choice of the exact composition, thickness, and number of these layers, it is possible to tailor the reflectivity and transmitivity of the coating to produce almost any desired characteristic.

The versatility of optical coatings leads to their use in many scientific optical instruments (such as lasers, optical microscopes, refracting telescopes, and interferometers),consumer devices such as display screens. binoculars, spectacles, and photographic lenses as well as ophthalmic lenses.

Such coatings are often complex multilayer systems deposited by expensive vacuum techniques. They can also utilise materials which are fragile or environmentally unstable. OAS has developed a novel single-layer wet chemical process anti-reflective coating which provides outstanding performance. This coating is based on low cost, stable materials and simple deposition techniques.