WHAT if you could capture light in a box? Lasers work on that very principle. Light is a wave and any colour is described by a particular wavelength. To trap light in a box, mirrors are used, with the dimensions specially chosen so that the light can reflect off the mirrors and “resonate” at its own wavelength.

Just like a musical instrument, these resonant waves reinforce each other. For a musical instrument, these reinforced waves come out as a sound wave making a note at a particular frequency, which is related to the wavelength.

In the case of a laser, light is trapped at a high intensity, again at a singular frequency related to the wavelength of the light. Some of the light is allowed to burst out of the container, seen as a laser beam.