IR Filters and Coatings
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 Number | CWL (nm) | Transmittance | FWHM (nm) | Suggested Use | Datasheet | Price | Buy Now |
|---|---|---|---|---|---|---|---|
| NBP-1940-42-25 | 1940 nm (+/- 8nm) | >85% | 42 nm (+/- 5nm) | H2O (Water) | See Datasheet | £250.00 | Buy Now |
| NBP-3055-145-25 | 3055 nm (+/- 16nm) | >75% | 145 nm (+/- 17nm) | C2H2 (Acetylene) | See Datasheet | £250.00 | Buy Now |
| NBP-3260-150-25 | 3260 nm (+/- 16nm) | >75% | 150 nm (+/- 17nm) | C2H4 (Ethylene) | See Datasheet | £250.00 | Buy Now |
| NBP-3330-150-25 | 3330 nm (+/- 15nm) | >75% | 150 nm (+/- 15nm) | CH4 (Methane) | See Datasheet | £250.00 | Buy Now |
| NBP-3349-70-25 | 3349 nm (+/- 15nm) | >75% | 70 nm (+/- 15nm) | C2H6 (Ethane) | See Datasheet | £250.00 | Buy Now |
| NBP-3400-155-25 | 3400 nm (+/- 15nm) | >75% | 155 nm (+/- 15nm) | (HC) General Hydrocarbon | See Datasheet | £250.00 | Buy Now |
| NBP-3900-180-25 | 3900 nm (+/- 18nm) | >75% | 180 nm (+/- 20nm) | (Reference) | See Datasheet | £250.00 | Buy Now |
| NBP-4000-180-25 | 4000 nm (+/- 18nm) | >75% | 180 nm (+/- 15nm) | (Reference) | See Datasheet | £250.00 | Buy Now |
| NBP-4260-160-25 | 4260 nm (+/- 20nm) | >70% | 160 nm (+/- 21nm) | CO2 (Carbon Dioxide) | See Datasheet | £250.00 | Buy Now |
| NBP-4530-85-25 | 4530 nm (+/- 20nm) | >75% | 85 nm (+/- 10nm) | N2O (Nitrous Oxide) | See Datasheet | £250.00 | Buy Now |
| NBP-4660-165-25 | 4660 nm (+/- 15nm) | >75% | 165 nm (+/- 15nm) | CO (Carbon Monoxide) | See Datasheet | £250.00 | Buy Now |
| NBP-5330-190-25 | 5330 nm (+/- 25nm) | >65% | 190 nm (+/- 25nm) | NO (Nitrogen Monoxide) | See Datasheet | £250.00 | Buy 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 Number | Description | Datasheet | Price | Buy Now |
|---|---|---|---|---|
| BPF-VIST-IRBL-25 | Visible Transmission from 400-600 nm and blocking for near IR and Mid IR. | See Datasheet | £250.00 | Buy Now |
| BPF-1.3-2.5-25 | Transmits from 1.3-2.5 µm and blocks outside this range. | See Datasheet | £250.00 | Buy Now |
| SWP-1.4-2.6-25 | 90% ave. Transmission for 1.4-2.6 µm, blocks from 2.7-20µm. | See Datasheet | £250.00 | Buy Now |
| LWP-1.65-25 | Long wave Pass filter, transmits above 1.65 µm and blocks below back to UV. | See Datasheet | £250.00 | Buy Now |
| BPF-2070-2510-25 | Mid IR wide band pass filter for 2070-2500nm , used for non contact temperature measurement | See Datasheet | £250.00 | Buy Now |
| BPF-3.0-5.0-25-Si | 90% Ave Transmission from 3-5 µm, blocks outside this to 7.5 µm on Silicon. | See Datasheet | £250.00 | Buy Now |
| BPF-3.0-5.0-25-SAP | 90% Ave Transmission from 3-5 µm, blocks outside this to 20 µm on Sapphire. | See Datasheet | £250.00 | Buy 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.
| Term | Explanation |
|---|---|
| Passband Average Transmission | This can be defined as the average transmission, in the passband, between the two points where transmission exceeds 80% of the peak value. |
| CWL | This 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. |
| FWHM | It 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 Filter | For 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 range | The 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. |
| Ripple | This 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. |
