ALUMINUM:
Aluminum mirrors and variable density filters are available in standard and custom sizes on
glass, plastic, and silicon wafers. The opacity or optical density of a film is a
function of film thickness. Figure 1 presents film transmission and optical density
as a function of film thickness. For films of sufficient thickness (greater than a
few hundred angstroms), the reflection of recently deposited aluminum is essentially
constant. Aluminum will oxidize over time and reflectivity will degrade. An overcoat
of magnesium fluoride is available for protection of the aluminum film against
oxidation. Figure 2 presents visible reflection in the visible for both freshly
deposited aluminum and protected aluminum.
Mirrors, optical density filters, and variable density transmission filters are available
on standard glass and plastic substrates. We also offer wafer aluminizing services.
 |
Figure 1: The transmission
through a thin aluminum film is a function of film thickness.
We fabricate standard and custom filters with variable transmission
and reflection. Applications include selective attenuation of
laser sources or improved uniformity of light sources.
|
 |
Figure 2: At sufficient
thickness, the reflectivity of an aluminum mirror is essentially
independent of further increases in film thickness, however,
the mirror oxidizes over time. A protective overcoat can be added
to extend the life of the mirror. Reflectivity of a protected
aluminum film, relative to a freshly coated aluminum film, is
plotted versus wavelength. A loss in visible reflectivity of
about 3% can be expected. |
Click here to request more information regarding our coating capabilities and thin film products.