Sapphire Windows
Sapphire
is highly transparent throughout the spectrum from 170 nm to 5.3 μm.
It has very high strength, hardness and chemical stability, making it an
excellent material for use as an optical window in adverse environments.
Sapphire
can be cleaned frequently without scratching.
It is five times stronger than glass and heat resistant up to 2000°C.
For these reasons, sapphire is often used in situations where large
pressure differences occur on either side of the window.
The
quality of the window can be critical. It
should be of high purity and polish in order not to affect the optical system.
Sapphire is an expensive material, which is difficult to polish, so it is
most often used in small sizes. Normally,
these windows are relatively thin. They
can be supplied with a low flatness specification ~4λ per 25mm or more
highly polished with a flatness of about λ/2.
We
offer standard uncoated circular sapphire windows: 12.7 and 25.4 mm either
Other sizes and configurations can be quoted on request.