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Metal
Coatings |
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Coating of metals like aluminum / silver / gold
on the polished glass surface increases the reflection and are useful
for many applications. These metals characteristically exhibit high
reflection over very broad wavelength regions. |
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Aluminum coated
mirrors are very stable and most
commonly used since aluminum gives reflection right from UV to IR
region.
Aluminum mirrors to be used in the visible region are usually
protected with a layer of Silicon Monoxide for durability. To increase
the efficiency of the coating and to make it even more durable,
enhanced aluminum mirrors are available for visible region which have
multiple dielectric layers on top of the aluminum to boost the
reflection.
UV aluminum mirrors are those which have high reflection
even in the UV region. These normally have a soft protective layer on
top of the aluminium coating, just to prevent the oxidation of
aluminium. |
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| UV
aluminium |
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Protected
aluminium |
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Reflection of Silver |
| Silver
has the highest
reflection in the visible region but is more expensive due to the
difficulties involved in the coating process. The coatings are not as
stable as aluminum. We give protected silver coatings which are as
durable as aluminium coatings. |
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Reflection of Gold |
| Gold coatings
can be used for reflection in IR region. |
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Dielectric high reflection coatings |
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Dielectric coatings are used when higher
reflection and durability is required as compared to metal
coatings. These can
be tuned for wavelengths from UV to IR region and for specific angle of
incidence. |
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| Reflector
for 266nm , 45° incidence, mean polarization |
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Reflector
for 500 - 600nm , 0° incidence |
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| Reflector for 700 - 900nm ,
0° incidence |
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Dielectric partial reflection Coatings |
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Dielectric coatings can also be tuned to get
partial
reflection. These are normally used at
normal incidence. and may have an anti-reflection coating on the second
surface. |
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| Partial
Reflector for 400-700nm, Average 25%R |
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Partial
Reflector for 500-800nm,
50%R |
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Partial
Reflector for 1064nm,
20%R |
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Partial
Reflector for 1064nm,
60%R |
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