Bandpass filters transmit
light only within a defined spectral band ranging from less than one
to many nanometers wide. Bandpass filters are used in spectral
photometry, clinical diagnostics, chemical analysis, colourimetry,
astronomy, and numerous applications where spectral isolation is required.
Single Cavity (SC)
bandpass filters provide very narrow bandwidths between 0.10 - 0.25nm
from the ultraviolet through the near infrared spectral regions.
filters are two-cavity designs with half bandwidth (HBW) typically
between 0.2 and 8.0nm.
series filters are three-cavity designs and feature HBW between 0.4
and 50nm in the ultraviolet to infrared spectral range.
filters are four and five cavity with HBW usually greater than 30nm
and up to several hundred nanometers in the UV, visible and IR
Discriminating Filters (DF)
have greater than 3,500 degrees phase thickness from numerous
interfering cavities, resulting in a bandpass filter with extremely
rectangular shape, very steep edges, and especially deep blocking
exceeding Optical Density (OD) 6 outside the passband.
Filters (RDF) are similar to DF filters, but are custom
engineered for applications requiring signal-to-noise of > 8
orders of magnitude over a limited spectral range.