The surprisingly simple physics of a laser

The laser is one of the most important tools for teasing cats.

In this article, I’ll show some properties of the atom and how the atom interacts with light. I’ll then use this knowledge to simulate a working laser.

This article is also available in a video format here

Light and atom interaction

The whole process of lasering relies on a special interaction between the atom and the light. So let’s examine an atom. For simplicity, let’s look at an atom with only one electron. Two states are shown by the two electron orbitals with a nucleus in the center.

The picture of the atom is completely wrong, but it gets the physics right because the distance between the two states represents energy levels for the electron.

As you know electrons can ONLY exist in a state and not in between two states. To switch state the electron will do a quantum jump: A transition to another state. But a transition…