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.
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General Specifications
| Diameter Tolerance: | +0/-0.25mm | |
| 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) | |
| Optical Quality: |
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 | |
| Specification Temperature: | +23ºC | |
| 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 |