ABSTRACT
A number of factors need to be considered when selecting materials for use in an optical thin film design. The optical dispersion properties of thin films can be found in published research literature. Titanium dioxide, also known as titania, is another widely used optical thin-film material, mostly because it has the highest refractive index in the visible spectrum and has a broad spectral transparency. Aluminum oxide, also known as alumina, is a hard film with a wide optical transparency. Magnesium fluoride is widely used in optical thin films because it has one of the lowest refractive indices. Silicon nitride is a popular thin film in the microfabrication area, especially in micro-electromechanical systems. Electronic applications require the silicon to be crystalline, but in optical thin-film applications, it can be amorphous or polycrystalline.
