Optical bandpass filters are designed to transmit a specific waveband.  They are composed of many thin layers of dielectric materials, which have differing refractive indices to produce constructive and destructive interference in the transmitted light

Fiber optic filters allow only specific wavelengths to pass into a larger fiber optic system

Long pass filters transmit a wide spectral band of long wavelength radiation while blocking short wavelength radiation. Short pass filters transmit a wide spectral band of short wavelength radiation and block long wave radiation

Spectral filters are used to selectively transmit light according to its wavelength. They are not to be mistaken with color filters, which can be differentiated by an associated schott glass number

Color filters include a wide range of filter types that are distinguished by their specific color spectrums and wavelengths, as well as their Schott glass compositions

Monochromators are optical subassemblies used to isolate narrow portions of a light spectrum. They accept polychromatic input from a lamp or laser, and outputs monochromatic light.

Interferometers measure distance in terms of wavelength and determine the wavelengths of light sources.

Spectral lamps radiate line spectra of various gases and metal vapors with high brightness and spectral purity.

Industrial filtration equipment is used to filter, thicken or clarify a mixture of different elements

RF filters and microwave filters are devices that pass or reject signals by frequency. Basic types include bandpass filters, band reject filters, low pass filters, and high pass filters

Liquid filtration elements are used to remove impurities from liquids. They are used in water treatment systems and fluid processing applications.

Filtration media and elements are designed to remove suspended particles from a process stream. This product area includes bulk filter media, cartridges, housing-only products, and housing and filter assemblies. 

Active filters are electronic filers that use active components such as voltage amplifiers or operational amplifiers. The amplifier shapes and stabilizes the behavior of the filter, and serves as a buffer interface to the driven component

Signal filters block or decrease (attenuate) unwanted frequencies or signal wave characteristics

Filter wheels hold and position multiple filters for various imaging applications such as machine vision and spectrophotometry