Can photons and atoms generate laser?

Shot of atoms floating.

NARRATOR: There's no real way to see what's going on inside an atom, like neon, when it absorbs or gives off light. But there are a few different models that tell the story.

Shot of three different models of an atom — Bohr model, staircase model, electron density model.

NARRATOR: The easiest model ignores the atom altogether and just looks at the energy of its electrons. Electrons in an atom can only exist at certain energy levels.

Shot of staircase model.

NARRATOR: A photon of green light has exactly the same amount of energy as the gap between two energy levels in neon. So when a green photon hits an electron at the lower energy level, the electron absorbs the photon and instantly has the energy of a higher level. After a fraction of a second, the electron jumps down to a lower energy level, giving off the energy difference as a photon of orange light.

Shot of green photon hitting electron.

Shot of photon of orange light being emitted.

NARRATOR: The models that try to show the atom aren't very accurate. The 100-year-old Bohr model is easy to draw, but electrons aren't really particles in rings around the nucleus. Each electron exists as waves. They're in a bunch of places at the same time, and they overlap. So the electron density model is our most realistic image of what an atom looks like. It's just harder to draw on a blackboard.

Shot of three different models of an atom.

Shot of atoms floating.