Diffraction Grating
An optical element with a periodic structure of thousands of closely spaced parallel rulings or lines that disperses light into its component spectral wavelengths.
Governing formula
d sin θ = m λ (m = 0, ±1, ±2, ...)
SI unit
m (slits per mm)
In depth
Multiple slit constructive interference produces extremely sharp, highly dispersed intensity peaks compared to double slits. Essential for high-resolution optical spectroscopy.
Examples in the real world
Rainbow reflection colors visible on the surface of a Compact Disc (CD) acting as a reflective grating with ~625 lines/mm.