By Hamish Johnston
Light is red, atoms are blue…
If light and atoms were people, what colour t-shirts would they wear?
Red and blue respectively — at least in a new educational video about the inner workings of the laser from physics blogger Clifford Johnson.
Johnson uses a group of people to represent the atoms and photons inside a laser — and how population inversion and stimulated emission result in the emission of coherent light. It could come in handy if you are teaching an introductory atomic physics or optics course.
The video is the second in a series by Johnson and funded by the US National Science Foundation. The first film is called Shine a light and is also on YouTube.