A diffraction grating is an optical glass substrate composed of dense and evenly spaced parallel lines, with an aluminum-coated reflective film on the surface. It can separate white light into various components through the diffraction effect. High-quality linear diffraction gratings can almost meet all diffraction requirements, especially when high efficiency is demanded. Diffraction gratings can be used in various monochromatic light research, teaching, and industrial Settings. Almost all commercial spectrophotometers use diffraction gratings to select specific wavelengths or scan the entire wavelength range. Customers can select gratings based on size, groove spacing and shining wavelength. This reflective line grating (blazed grating) has a sawtooth shape and is different from holographic gratings.