Processes

Multilayer optical coatings are important in a wide range of precision optics applications including lighting for colour/ heat control, fibre optical telecommunications, imaging optics, displays and sensors. Visible optical coatings include anti-reflection coatings to maximise transmission and minimise glare, blocking filters to control exposure to IR and/or UV; edge and notch filters to control colour contrast and narrow band filters for selection of specific wavelength ranges.

Traditionally, for these applications, PVD techniques are utilised including electron beam deposition and evaporation. Closed field magnetron sputter deposition is rapidly emerging as a preferred alternative for deposition of precision optical coatings in a wide range of applications including:

Typical dielectric thin film materials for visible application include SiO2, Nb2O5, TiO2, Ta2O5. Multilayers combining SiO2 and a high index material are deposited to create a wide range of spectral characterisitics such as anti-reflection coatings, blocking and narrowband filters.

Closed field magnetron sputtered coatings also provides low absorption and minimal defect density/ particle inclusions, making the technique suitable for high laser damage coatings.