A bandpass filter is an inexpensive optical filter used as a wavelength selector that allows transmission of a predetermined wavelength while rejecting or blocking other wavelengths. Along with our wide selection of standard infrared filters, Optometrics designs and manufactures custom bandpass filters for instrument manufacturers world wide.
- Clinical chemistry instrumentation
- Spectral radiometry
- Environmental testing
- Elemental and laser line separation
- Flame photometry
- Color separation
Optical Bandpass Filter – Typical Transmission Curve
Transmission Curves are graphs or mathematical functions that characterize optical filters. Typically expressed as the percent or fraction of light transmitted versus wavelength.
- Bandwidth is a range of wavelength that specifies the transmitted part of the spectrum.
- Central Wavelength (CWL) is the midpoint wavelength of the bandwidth.
- Peak Transmittance is the maximum percentage of light transmission through the filter. It is often centered at the CWL, but many filters have fairly flat transmittance across the bandwidth.
- Half Bandwidth (HBW) or Full Width-Half Maximium (FWHM) is the wavelength range that characterizes a bandpass filter. It is bound by the wavelengths where transmittance is half (50%) that of the peak transmission.
- Upper and Lower Blocking Regions are the ranges of wavelengths where the light is attenuated.