Bandpass Filters select a very specific range of light by transmission. This Band can range from very narrow (<1% of the wavelength) to relatively wide (>10% of the wavelength). The unwanted wavelengths are blocked by reflection, absorption or a combination of both. Such Filters are specified by Central Wavelength (CW), Bandwidth (FWHM), Peak Transmission, and Blocking range/level. The cone angle of use is traditionally small (several degrees) but Bandpass Filters are increasingly being designed and manufactured to accommodate larger angles.
The operational wavelength region can be selected from the range 200-8000nm to suit the application.
Bandpass Filters can now be designed and produced in many different sizes, shapes and thicknesses by selection of the most suitable construction technology.