Silicon is typically used as an optical window in the 3-5 micron region.  It is also used as an optical filter.  Silicon has low density and high thermal conductivity making it an ideal material to be used for laser mirrors.  Silicon is grown by two different forms.  One, is Czochralski (CZ), which contains some oxygen which causes an absorption band.  The other is Optical Quality Silicon.  Optical Quality Silicon is typically doped and because it has a high refractive index it must be anti-reflective coated to achieve a high optical transmission.

MPF Products, Inc. does not approve the use of ultrasonic cleaning for any viewport.  We ship our viewports UHV ready.  You may simply blow off the glass to remove any contaminants with clean, dry air.  For additional cleaning steps for particulates or contamination from other processes, please review our cleaning procedures at

Bake-Out Ramp Rate: 20°C per Minute