ruby laser

A ruby laser is a device that produces red light through an atomic transition of chromium within a ruby rod. This technology emerged from Albert Einstein's 1916 suggestion that atoms could release energy as light, either spontaneously or when stimulated.12

The development of the laser involved key figures like Charles H. Townes, Rudolf Walther Ladenburg, and Arthur L. Schawlow, building upon the principles of stimulated emission. Theodore H. Maiman successfully created the first ruby laser in 1960 by exciting chromium atoms in a synthetic ruby crystal with flashes of light. This process relies on quantum mechanics, where atoms absorb energy to reach an excited state and then release it as light when electrons drop to lower energy levels. A ruby laser operates on a three-level system, where excitation leads to a metastable state that allows for stimulated emission.23