As its name suggests, an extended range viewport or transmission port is an optical component that provides for transmission of radiation in either the ultra violet or infrared portion of the electromagnetic spectrum. Standard viewports made of either fused silica or sapphire have useful transmission from 0.25 microns to 2.5 or 4.0 microns respectively. Extended range window materials have a combined transmission range from 0.12 microns to 20.0 microns. Typical applications for Extended Range Viewports include CO2 lasers, YAG lasers, Excimer lasers, Spectroscopy, and Thermal Imaging.

Of course no single window material can offer good transmission over the entire spectrum. Alkali halides such as calcium fluoride, CaF2, or magnesium fluoride, MgF2 , offer excellent transmission in the deep ultraviolet. Polycrystalline CVD grown infrared transmitting materials such as zinc selenide, ZnSe, and Zinc sulfide, ZnS transmitted radiation out to nearly 20 microns.

Many factors govern the selection of optical materials for the construction of a high and ultra-high vacuum assembly. Whereas quartz and sapphire can be readily metalized and sealed to vacuum flanges by brazing, most optical materials are too weak to join to by high temperature joining processes. Further, many optically transmitting materials are strongly hygroscopic (such as sodium chloride) or melt at low temperatures (such as glass). The physical and chemical properties of Ceramaseal's extended range transmission ports have been selected on the basis of optical transmission, vacuum compatibility, strength of materials and widespread usage by optical engineers.

As always, Ceramaseal's team of engineers can CUSTOM DESIGN a solution for your demanding application! Whether it is a CVD cluster tool or a linear accelerator R&D program, let Ceramaseal provide the higher level assembly for you!

Based in New Lebanon, N.Y., Ceramaseal is a division of CeramTec North America. Ceramaseal has been in the ceramic-to-metal seal industry for more than 50 years. Ceramaseal is an ISO-9001 certified company that manufactures a wide range of standard and custom ceramic-to-metal sealed components.