coatings created by other means. Of prime
importance is that deposition takes place
at room temperature.
Using atomic force microscopy9 (AFM),
Figure 4 shows the surface micromorphol-ogy of a 2-μm-thick silicon film deposited
by conventional thermal evaporation at
room temperature. The resultant film morphology exhibits a rough, poorly nucleated, nonadherent columnar porous film.
Figure 5 is an AFM evaluation of a 2-
μm silicon film created at room temperature by the reactive ion plating. In this
case, the film is fully adherent, smooth
and featureless, indicative of a fully densified bulklike thin-film structure.
Protected gold alloy-replicated mirrors
Replicated mirrors produced with Darius’ alloy subsequently were coated with
elemental silicon at room temperature
using RLVIP. A film thickness of 70 nm
was employed to tune the optimal spectral
performance for the desired 1580- to
15,000-nm spectral region. A silicon film
thickness of 160 nm was used for creating
mirrors for the alternative 1300- to 1700-
nm band. The resultant measured reflectances demonstrate that these surface-
Figure 4. This AFM image shows the surface micro-morphology of a 2-µm-thick silicon film deposited
by conventional thermal evaporation at room temperature.
Figure 5. An AFM evaluation of a 2-µm silicon film
was created at room temperature by Newport’s
patented Reactive Low Voltage Ion Plating process.
modified replicated mirrors are indeed
well suited to critical infrared instrumentation applications (Figures 6 and 7).
For a comparative measurement of surface hardness and abrasion resistance, the
moderate abrasion methods as described in
MIL-M-13508C were re-employed. In
both of the above cases, RLVIP-protected
replicated gold alloy mirrors survived beyond 350 strokes without visible evidence
of any surface abrasions.
Learning from the past
Many ancient civilizations have contributed to our current modern scientific
understanding. Countless groundbreaking