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Knight Optical(UK) Ltd - [email protected] - +44 (0)1622 859444

Infrared filters

What are you looking for in Stock?

This stock range is currently in development. Knight Optical already supplies high quality custom IR filters to industries worldwide.

More details about our individual product capabilities can be found through the links below or via our experienced technical sales team. Sign up to our regular newsletter for the latest information on upcoming Knight Optical products and releases.

 

Knight Optical is able to supply stock optics for use in the IR (1to 100µm) wavebands.  Infrared Optical filters that are custom made to your specification include:

Interference bandpass filters: comprise; narrow pass, standard pass, wide pass, and Filter sets.  These filters are made using IR substrates such as silicon, sapphire, IR Quartz and germanium etc. with thin films of material that have differing refractive indices and thickness.  The filters are usually used on-axis as a difference in angle from zero will increase the path length of the rays through the filter.  This has the effect of moving the pass band toward longer wavelengths.  The filters are used to isolate, for example, emission lines from a source or fluorescent from background.  Laser lines can be isolated to maximize the signal relative to noise ratio.


Long wave pass filters: comprise individual and boxed set.  These filters are made using IR substrates such as silicon, sapphire, germanium, IR quartz etc. with thin films of material that have differing refractive indices and thickness.   The filters are used to block the short waveband and transmit the long wavelength and therefore serve to remove any non-required wavelengths and transmit the required ones.  These filters can help with reducing the noise and thus improve the signal to noise ratio.  They can be used in combination with the short wave pass filters to form a bandpass filter.   This combination can have variable bandwidths that are tuned by the use of different long and short pass filters.

Short wave pass Filters: comprise individual and boxed set.  These filters are made using IR substrates such as silicon, sapphire, germanium etc. with thin films of material that have differing refractive indices and thickness.   These filters block the long wavelengths and transmit the short wavelengths and therefore serve to remove any non-required wavelengths and transmit the required ones.  These filters can help with reducing the noise and thus improve the signal to noise ratio.  They can be used in combination with the long wave pass filters to form a bandpass filter.  This combination can have variable bandwidths that are tuned by the use of different long and short pass filters.

Neutral density filters: comprise individual and boxed sets.  These filters can be made from thin films, varying blackness glass and plastic substrates.  These filters have various levels of transmission across a broad spectrum of wavelengths.  The filters are usually consist of a range from 0 to 1 in 0.1 OD and then every 1 OD from 1 OD to about 10 OD.  An OD is defined as ten times the log (base 10) of the transmission, for example, a 1OD transmits 10%, and 2 OD transmits 1%.  Sets are available for OD 0.1 to 1, 1 to 10, and the two sets as one set.  These filters will have transmission wavebands in the 1 to 6µm with, usually, Silicon substrates and in the thermal waveband of 8 to 12µm on, usually, Germanium substrates.  Other densities and substrates are available.

Gas band filters: comprise individual and boxed sets.  These filters are usually made using IR substrates such as silicon, sapphire, germanium etc with thin films of material that have differing refractive indices and thickness.  manufactured using thin films as narrow pass band filters are needed and a blocking of at least 3 OD.  The filters are used to detect the gas, for example, methane, from the background signal, such as our atmosphere. 

Semiconductor filters: comprise individual and boxed sets.  These filters are manufactured by modifying the mineral make-up of the semiconductor medium.  The filter works by absorbing photons, which is done by the photon supplying energy to an electron in the valence band and lifting it across the band gap to the conduction band.  If the photon is not energetic enough to cross this band gap, then the photon is transmitted provided the valence band energy levels are completely filled.  This abrupt change in transmittance and absorbance is termed the intrinsic edge, and it is caused by the photons with sufficient energy to cross the band gap, thereby producing a long pass filter.  Typical materials are: Gallium Arsenide with a cut on at 0.9µm, Silicon at 1.04µm, Germanium at 1.7µm and Indium Arsenide at 3.6µm.

Knight Optical supply high quality IR Optical Filters optical components made to your specific bespoke custom specification.  Every component is individually tested by our highly skilled technicians in our state of art metrology lab to ensure all components meet our high quality standards.

Contact our multilingual technical sales team and discover how Knight Optical’s high quality IR Optical Filters and service can improve your instrumentation and supply chain experience.


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Our Multi-Lingual Sales Team are here to help with your requirments:

UK +44 (0)1622 859444
UK +44 (0)1622 850614
UK +44 (0)1622 851078
+1 401 583 7846

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