S1 Optics coats various substrates such as glass, metal, plastic and crystal with dielectric and metal layers. Selection of the substrate in this process depends on a variety of factors including transparency, chemical, thermal and mechanical stability, thermal conductivity, specific weight, formability etc. The substrates are then used in a wide variety of applications.
Glass products such as BK7, Borofloat and Corning, for example, continue to be the first-choice substrate material for optical coatings. They are characterized by high chemical and thermal strength, transparency and mechanical stability.
Metals are particularly suitable for coatings which reflect and absorb. Their good thermal conductivity means they can be used in areas where high levels of heat from radiation output need to be dissipated.
For some years, there has been a trend towards replacing glass with plastic if possible. The advantage of this material is in its low weight, its ease of forming and the fact that most plastics do not shatter in the event of mechanical damage.
In addition to the types of substrate mentioned, crystalline substrates such as sapphire, MgF2, CaF2 and ZnSe are used for optical coatings. These materials are used primarily in laser optics as windows, mirrors or focussing lenses.