Infrared Optical Interference Filters
Narrow Band Pass Filters
Narrow bandpass filters are designed
to isolate a narrow region of the infra-red spectrum.
This is accomplished using a complex process of
constructive and destructive interference.
Narrow band pass filters have
bandwidths (measured at half-peak transmittance levels)
less than 6% of the center of wavelength value. When
ordering, the bandwidth can be expressed as a percentage
of the center wavelength, or can be given in microns.
The filters exhibit high peak
transmission (typically greater than 60%) combined with
high attenuation levels outside the passband (typically
less than 0.1%).
Typical Performance

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Typical Characteristics
| Available
wavelength range |
~1 to 20um |
| Tolerance on
CWL |
To customers requirements, but standard
tolerances are typically +/-0.3% for a 1%
bandwidth filter to +/-1% for a 6% bandwidth
filter
|
| Peak transmittance |
Typically >60% (depending on wavelength and
bandwidth) |
| Available bandwidths |
Typically 0.9% to 6% |
| Blocking (attenuation) |
Typically <0.1 % from 0.3 micron to far
infrared |
|