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UV Filters

interfence bandpass filters from Knight OpticalKnight Optical can provide UV filters designed to transmit in the germicidal UVC waveband between 200-280nm. These filters are used to ensure only certain wavelengths enter or leave an optical system. Knight Optical can provide both UV bandpass filters, for specific UVC wavelengths, and UV shortpass filters which transmit through the UV region.

UV Interference Bandpass Filters

Interference bandpass filters are used to only transmit certain wavelengths and, for UVC sterilisation, this often corresponds to the main desired wavelength transmitted by a light source, and ensuring light either side is sufficiently blocked:

  • Krypton-chloride (KrCl) excimer lamps – 222nm
  • Low-pressure mercury lamps – 254nm
  • UV LEDs – 265nm, 273nm and 280nm

Knight Optical can provide stock mounted UV bandpass filters manufactured using thin film layers of dielectric coating. All blocking regions are OD4 or better, ensuring that all undesired wavelengths do not enter a system or detector.

UV Colour Glass Filters

Knight Optical can supply UV colour filters which transmit primarily in the UV region whilst blocking the visible region from 400nm onwards. We stock three main UV colour glass bandpass filters – UG1, UG5 and UG11 either as 25mm diameters or 50x50mm squares, however we can also provide custom dimensions when requested. The benefit of colour glass filters is that the transmission is independent of the angle of incidence and are therefore easier to integrate within a system. As well as standard filter glass, Knight Optical can also provide moulded UV filter glass for more complex designs.

Please do not hesitate to contact our technical sales team who will guide you through your enquiry regarding our UV moulded optics.
With our in-house state-of-the-art metrology laboratory you can be confident that your optical components will meet your requirements. You can find out more about our testing facilities here.

Far-UVC Light – 207-222nm

  • When it comes to UV sterilisation and disinfection 222nm is becoming a more popular wavelength choice.
  • This particular wavelength still shows germicidal properties like the rest of the 200-280nm waveband but, unlike the slightly longer wavelengths, 222nm is less harmful to humans, meaning systems using the 222nm wavelength can operate in more communal areas.
  • Currently, the main light source is an excimer lamp using a krypton chloride (KrCl) gain medium. LEDs are available but they are not as efficient as the more commonly used UV LEDs.

Knight Optical can provide custom 222nm bandpass filters manufactured to our customers specifications.

Knight Optical can also provide optical domes manufactured from UV fused silica, for more standard domes, or from moulded UV glass, for more complex designs.