Zinc Selenide Zero Length Viewports

VacTechniche Vacuum Optics – Viewports

Zinc Selenide Zero Length Viewports

VacTechniche zinc selenide viewports are offered in CF, ISO and KF flange styles. The viewports comprise a laser quality zinc selenide optic with precise flatness, parallelism, scratch and dig specifications. The ultra high vacuum (UHV) CF versions are offered using high grade 304L or 316LN stainless steel flanges. Non-magnetic viewports are offered for low energy applications or surface science applications needing low magnetic fields.



The non-magnetic viewports use a non-magnetic weld ring instead of the regular kovar weld ring. Flanges in 316L stainless steel are used for the high vacuum KF and ISO viewports. VacTechniche viewports are manufactured in clean room conditions and helium leak tested, cleaned and packed to UHV standards.

The rugged construction of the zinc selenide viewports allows bake-out to a maximum of 120 °C with UHV performance, whilst the window offers broadband optical transmission to extreme infrared. Options with anti-reflective coatings are also offered. Non-standard viewports can be manufactured on request, including re-entrant style microscope/camera viewports. Annealed copper gaskets and other component accessories are also supplied by VacTechniche.

Transmission Curve – Zinc Selenide


Seal Type Bond
Maximum Temperature 120 °C
Minimum Temperature minus 45 °C
Maximum Rate of Temperature Change 3 °C per minute
Leak Rate <1×10-10 atm-cc/sec (He)
Pressure Range 1 bar to 1×10-9 mbar
Surface Quality 60/40 scratch/dig
Flatness <2λ

Cross Sections / Diagrams

Parts & Variations

Part Number Flange Type OD mm View Diameter mm Optic Thickness mm Flange Thickness mm Flange Material Weld Ring Material Non-Magnetic
BVPZ16ZnSe NW16CF 34 15 1.5 12.7 304L Kovar
BVPZ16ZnSe-LN NW16CF 34 15 1.5 12.7 316LN Kovar
BVPZ38ZnSe NW35CF 70 32 3 12.7 304L Kovar
BVPZ38LAZnSe NW35CF 70 38 3.75 12.7 304L Kovar
BVPZ38ZnSe-LN NW35CF 70 32 3 12.7 316LN Kovar
BVPZ38LAZnSe-LN NW35CF 70 38 3.75 12.7 316LN Kovar
BVPZ64ZnSe NW63CF 114 63 5 17.4 304L Kovar
BVPZ64ZnSe-LN NW63CF 114 63 5 17.4 316LN Kovar
BVPZ100ZnSe NW100CF 152 89 6.5 19.9 304L Kovar
BVPZ100ZnSe-LN NW100CF 152 89 6.5 19.9 316LN Kovar