About Bandpass Filters
The use of bandpass filters is one of the simplest and most economical ways to transmit a well-defined band of light and to reject all other unwanted radiation. Their design is essentially a thin film Fabry-Perot interferometer formed by vacuum deposition, and consists of two reflecting stacks separated by an even-order spacer layer.
Because the Fabry-Perot filter is Lorentzian in shape, the cut-on and cut-off slopes are shallow and the rate of attenuation in the out-of-band blocking range is slow. To improve the slopes and increase the attenuation in the blocking band, we introduce more cavities into the construction of our standard dielectric bandpass filters.
|Usable Aperture:||Filter Size||Usable Aperture|
|12.5mm Ø||9.0mm Ø|
|25.0mm Ø||21.0mm Ø|
|50.0mm Ø||45.0mm Ø|
|Surface Quality:||80-50 (Per MIL-PRF-13830B)|
Commercial instrumentation grade
(TWF 3-5 waves per inch
Parallelism 3-5 arc/minute)
|Out-of-Band Blocking:||1 x 10-4 avg. from X-ray to FIR|
|Max. Survival Temp Range:||CW/L 214-380nm||-50ºC to +50ºC|
|CW/L 380.1-2400nm||-50ºC to +70ºC|
|Humidity Resistance:||Per MIL-C-48497A|
|Mechanical:||Mounted in an anodized aluminum ring|