The Diffraction Grating
A diffraction grating is typically made from a piece of glass or plastic upon which parallel grooves are ruled very close together, many thousands per centimetre. A diffraction grating is an optical component that separates polychromatic light into its component wavelengths. The high-quality and high-precision process required for grating manufacturing gives the flexibility to design various diffraction grating instruments. Instruments such as wave division multiplexers, light spectrum analysers, and fibre amplifiers, use diffraction gratings as components. There are two categories of gratings that describe the method of manufacturing gratings: ruled and holographic gratings. Both reflection and transmission gratings separate white light into the spectrum of colours. Transmission grating beamsplitters are commonly used for laser beam division and multiple laser line separation in visible wavelengths. A reflective diffraction grating consists of very closely spaced sets of parallel or circular lines or grooves made in the mirror surface of an optical material.