How do dopants help crystal and glass lasers produce light?

In crystal and glass lasers, dopants function as the active light-emitting atoms that are added to a host material at low concentrations. These dopants are essential because they provide the specific energy levels required for laser action.12

When an external light source is applied—a process known as optical pumping—the dopant atoms absorb photons, which raises their electrons to a higher energy state. This process creates a population inversion, a state where more atoms exist in higher energy levels than in lower ones. Once in this excited state, the dopant atoms can be triggered to release their stored energy as light. When this occurs within a suitable resonant cavity, the light is amplified to produce a laser beam.3412

Common examples of these dopants include neodymium, erbium, and ytterbium, which are frequently used in various crystal and glass laser applications.1