IR Filters and

We design and manufacture a wide range of IR Filters from 0.7-6.0µm.

A range of Narrow Band Filters (for gas and chemical detection) and a range of general IR filters are available from our web-shop see below.

Custom filters can be manufactured with short lead-times, contact us to find out more.

Stock Narrow Band Filters


We have a wide range of ‘off the shelf’ filters for detection of common gases and materials, these can be bought online now, see full details and specifications below. All filters are sold as 25mm diameter, 0.5mm thick.

Part Numbers Explained

Part NumberCWL (nm)TransmittanceFWHM (nm)Suggested UseDatasheetPriceBuy Now
NBP-1940-42-251940 nm (+/- 8nm)>85%42 nm (+/- 5nm)H2O (Water)See Datasheet£250.00Buy Now
NBP-3055-145-253055 nm (+/- 16nm)>75%145 nm (+/- 17nm)C2H2 (Acetylene)See Datasheet£250.00Buy Now
NBP-3260-150-253260 nm (+/- 16nm)>75%150 nm (+/- 17nm)C2H4 (Ethylene)See Datasheet£250.00Buy Now
NBP-3330-150-253330 nm (+/- 15nm)>75% 150 nm (+/- 15nm)CH4 (Methane)See Datasheet£250.00Buy Now
NBP-3349-70-253349 nm (+/- 15nm)>75%70 nm (+/- 15nm)C2H6 (Ethane)See Datasheet£250.00Buy Now
NBP-3400-155-253400 nm (+/- 15nm)>75%155 nm (+/- 15nm)(HC) General HydrocarbonSee Datasheet£250.00Buy Now
NBP-3900-180-253900 nm (+/- 18nm)>75%180 nm (+/- 20nm)(Reference)See Datasheet£250.00Buy Now
NBP-4000-180-254000 nm (+/- 18nm)>75%180 nm (+/- 15nm)(Reference)See Datasheet£250.00Buy Now
NBP-4260-160-254260 nm (+/- 20nm)>70%160 nm (+/- 21nm)CO2 (Carbon Dioxide)See Datasheet£250.00Buy Now
NBP-4530-85-254530 nm (+/- 20nm)>75%85 nm (+/- 10nm)N2O (Nitrous Oxide)See Datasheet£250.00Buy Now
NBP-4660-165-254660 nm (+/- 15nm)>75%165 nm (+/- 15nm)CO (Carbon Monoxide)See Datasheet£250.00Buy Now
NBP-5330-190-255330 nm (+/- 25nm)>65%190 nm (+/- 25nm)NO (Nitrogen Monoxide)See Datasheet£250.00Buy Now

General IR Filters and Coatings


We manufacture a range of IR filters for applications such as non-contact temperature measurement, filter wheels and machine vision, available online below.

Part NumberDescription DatasheetPriceBuy Now
BPF-VIST-IRBL-25Visible Transmission from 400-600 nm and blocking for near IR and Mid IR.See Datasheet£150.00Buy Now
BPF-1.3-2.5-25Transmits from 1.3-2.5 µm and blocks outside this range.See Datasheet£150.00Buy Now
SWP-1.4-2.6-2590% ave. Transmission for 1.4-2.6 µm, blocks from 2.7-20µm.See Datasheet£150.00Buy Now
LWP-1.65-25Long wave Pass filter, transmits above 1.65 µm and blocks below back to UV.See Datasheet£150.00Buy Now
BPF-2070-2510-25Mid IR wide band pass filter for 2070-2500nm , used for non contact temperature measurementSee Datasheet£150.00Buy Now
BPF-3.0-5.0-25-Si90% Ave Transmission from 3-5 µm, blocks outside this to 7.5 µm on Silicon.See Datasheet£150.00Buy Now
BPF-3.0-5.0-25-SAP90% Ave Transmission from 3-5 µm, blocks outside this to 20 µm on Sapphire.See Datasheet£150.00Buy Now

Rockard Technology

Our IR Filters are deposited by sputtering using our ‘Rockard’ © technology, traditionally thermal evaporation has been used for IR filters. Our technology ensures the following:


  • Highly durable coatings suitable for the toughest environments.
  • Extremely low temperature shift.
  • Reduced passband ripple for even response.
  • High blocking efficiency to increase signal to noise ratio.

Sputtering Vs Thermal Evaporation

Sputter deposition has a process energy approximately 3x that of thermal evaporation, this is responsible for the densely packed structure. This structure leads to superior environmental properties as outlined below.

Traditional Thermal Evaporation

  • Voids in coating.
  • Poor environmental performance.
  • High shift with temperature change.

Open structure of traditionally evaporated coatings with gaps and voids.

Sputter Deposition

  • Voids eliminated.
  • Excellent environmental performance.
  • Extremely low temperature shift.

Densely packed sputtered coating with no gaps
or voids.

Technical Terms for specifying Filters

Terms used for specifying Wide Band Pass Filters and Narrow Band Pass Filters, see the diagrams and explanations below.

Passband Average TransmissionThis can be defined as the average transmission, in the passband, between the two points where transmission exceeds 80% of the peak value.
CWLThis is the Centre Wavelength of the passband of the Filter, (see right hand figure above). The CWL is the distance in nm between the two points that are 50% of the peak Transmission.
FWHMIt stands for 'Full Width Half Maximum' but is also referred to as the 'width of a filter'. It is measured between the two points in nm or microns where Transmission equals half the maximum transmission.
Slope of a FilterFor an edge filter this is the gradient of the filter expressed as a a percentage, the lower the value the steeper the edge. A bandpass filter has two slopes, see left hand diagram above.
Slope of a filter (Left handside)The left hand slope is calculated as follows, (ʎ 80% of Peak T in nm-ʎ 5% of Peak T in nm)*100/ʎ 5% of Peak T in nm, (see left diagram above)
Slope of a filter (Right handside)The right hand slope is calculated as follows, (ʎ 5% of Peak T in nm-ʎ 80% of Peak T in nm)*100/ʎ 80% of Peak T in nm, (see left diagram above)
Blocking rangeThe band over which the filter has a Transmission of near zero, this can be specified as the detector sensitivity range plus a 10% safety margin. It can also be defined with reference to the system illumination range.
RippleThis normally refers to the allowed variation between maximum and minimum in the pass band of a filter. For example ripple variation to be< +/-5% form the passband average.