Product Overview
Bandpass coatings transmit only a limited range of wavelengths, while a broad range of wavelengths are effectively blocked (i.e. reflected and/or absorbed). They are widely used wherever there is a need to separate signals from ambient background. Narrow bandpass filters are generally defined as those in which the bandwidth (FWHM) is 10% or less of the center wavelength (e.g. 100 nm FWHM for a 1000 nm center wavelength filter). Wide bandpass filters are just the opposite. Dual bandpass filters feature two passbands, rather than a single one.
The DSI Difference
DSI has extensive experience designing and manufacturing bandpass coatings for use at wavelengths ranging from the visible through the mid-wave infrared. These include broad bandpass, narrow bandpass and even dual (or multi-wavelength) bandpass designs. DSI bandpass filters are characterized by high in-band transmission, strong out of band blocking and immunity to shifts due to changing humidity.
