ruling engine

A ruling engine is a highly precise machine used to create the fine, parallel lines on a diffraction grating. These gratings are essential components in optical devices, used to separate light into its constituent wavelengths, forming a spectrum.

The ruling engine, first used in 1826, typically employs a diamond-tipped tool to etch thousands of lines onto a polished surface. Modern techniques also utilize photographic methods with laser interferometry. Diffraction gratings work based on the principle of diffraction and interference, allowing for the resolution of very closely spaced spectral lines. This precision is crucial for various optical applications, especially in the infrared and ultraviolet regions where lenses may absorb radiation.12