Monochromatic filter, generally using interference filters, and can filter cut-off, cold (reflected) light, subtractive color filters, frustrated total anti-interference filters and induced transmission interference filter, in addition to monochromatic optical filter consisting of two pieces of glass, but a wide band.

Monochromatic light: ideal monochromatic light should is Dan Pinguang, for without beginning or end of sine wave, but actually only get very narrow band of more frequency light, for sine wave of mixture, called composite light, and miscellaneous collection light, and more color radiation, certainly more clear of also is associate monochromatic light, usually is called monochromatic light or more frequency light, usually get of spectral lines that so, if promotion to not see of radiation, is logical to has monochrome radiation.