Optical Filters

Optical Filters selectively transmit light of different wavelengths by blocking a specific wavelength or range of wavelengths. They are plastic or plane glass filters, the optical properties of which are described by their frequency response. Optical filters broadly fall into 4 categories; Notch filters reject a portion of wavelengths while transmitting the rest of the spectrum; Interference filters that contain interference coatings so they transmit a selection of the spectrum while blocking the rest; Substrate filters are absorption filters that use the materials transmission and absorption properties and ND filters reduce transmission evenly across a selected portion of the spectrum. Optical filters are widely used for Photography purposes where photographic filters are desirable and are also useful for some scientific and technical work.