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Vacuum Technology

From the vacuum-compatible screw to the complete vacuum chamber.

Vacuum Viewports

The transfer of electromagnetic waves, e.g. in the form of light or laser waves, from the outside into the vacuum or from the inside out of the vacuum is required for many vacuum technology applications. Sight glasses are preferably used when the target object in the vacuum chamber can be reached directly or by simple beam deflection of the light wave. For the window itself, optical materials with low absorption in the desired spectral range are selected, which show the lowest possible losses during transmission for a given thickness.

Diverse Product Range

The possible applications of vacuum viewing glasses can generally be divided into two areas. On the one hand, they can be used for the illumination and observation of processes in a vacuum. The standard sight glasses from VACOM are optimally suited for this application due to the maximum free viewing diameter and the transparency in the entire visible spectrum. For more specialised optical applications, we offer corresponding sight glasses with high-precision window surfaces for laser applications or optical materials with high transmission outside the visible range for applications in the UV and IR range. It is also possible to optimise the sight glasses for the wavelength range used by means of anti-reflective coatings. Various joining technologies and material combinations are available to suit your vacuum requirements. For the use of sight glasses in environments where there is a risk of contamination or high-energy radiation, we offer additional accessories such as sight glass covers and radiation protection caps.

Our range:

  • Standard sight glasses
  • Sight glasses for optical applications
  • HiPO - High Precision Optics Series
  • AluVaC® Optics
  • Viewport shutters optionally available
  • Special sightglasses and additional components


By using a manually operated viewport shutter, the sight glass can be shielded from material deposits on the vacuum side, e.g. during a vapour deposition process, thus avoiding any impairment of the transparency. The shutter is mounted between the sight glass and the connecting flange of the vacuum system via a double-sided CF through-flange. A magnetically coupled rotary feedthrough ensures hermetically sealed operation and allows use in UHV / XHV. 

The viewport shutters of the MeTraVaC® series are offered in the CF standard in the nominal widths DN40, DN63, DN100 and DN160. Their characteristic values:

  • for vacuum-side shielding of a sight glass
  • double-sided through flange with through holes
  • complete covering of the orifice opening
  • swivelling via magnetically coupled rotary union
  • with overwind protection and locking screw
  • with return spring for automatic closing
  • can be used in any installation position
  • Helium leakage rate 1 ⋅ 10-10 mbar⋅l/s
  • bearings coated with molybdenum disulphide (MoS₂)
  • completely bakeable up to 250 °C

Are you looking for suitable viewport shutters?

Perfect viewports for your individual application

An experienced team of optics specialists, material scientists and vacuum technicians is looking forward to finding a suitable solution for your special application. Just ask us.

Samples of products

    UHV borosilicate viewport, standard | Order no: 303186
    Borosilicate KF/ISO Viewport, Standard | Order no: 302261
    Radiation protection caps, for CF flanges | Order no: 306220
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