Optical Filter is a device that transmits light selectively of different wavelengths. It is used as a plane glass or plastic devices in any optical path. The optical properties and features of the filter are shown by its frequency response that fuehrer demonstrates the degree and phase of each frequency component.

This selectively transmits light in a fixed range of wavelengths. It can easily pass long wavelengths, short wavelengths or band of wavelengths that blocks shorter as well as longer wavelengths. The created passband is wider or narrower and the transition between maximal and minimal transmission is sharp or gradual. This is widely used for photography in many optical instruments, scientific and technical work.  It is also used in astronomical domain for restricting light passed to the spectral band of interest. In addition, it has also become a vital part in fluorescence applications like fluorescence microscopy and spectroscopy.

Features of Filter: