THE WORLD'S MOST POWERFUL LASERS

What happens when a beam of energy 100 times the power of the global electricity grid is concentrated onto a pinpoint?

- WORDS AILSA HARVEY

Lasers are devices that produce a narrow beam of polarised light. However, unlike the beam of a torch, a laser's light can carry extraordinary amounts of energy. When focused to a narrow point, lasers can cut or melt metal and even generate enough energy to replicate conditions in deep-space environments such as the inside of a star.

A laser's three main components are an energy source, a gain medium and an optical resonator. The first component, also known as a pump, is the energy that excites the medium, often using an electric current. The gain medium is a material that amplifies the light before it's directed through the optical resonator, an arrangement of mirrors, for further amplification as light is reflected multiple times through the gain medium.

Lasers are classified based on their strength, with the least powerful being class I and the most powerful being class IV. Their power is expressed in watts, with each watt the equivalent of one joule of energy emitted every second. Class I is not a hazard and poses no risk to human skin or eyes, while class IV lasers are those with a power output above 500 milliwatts. These can cause fires and are used for industrial applications.

The most powerful lasers can reach levels far above this, however, in the order of petawatts of power - a petawatt is 1,000,000,000,000,000 watts. With lasers this powerful, scientists can vaporise matter, create matter from light and mimic the conditions of a black hole. This means materials and conditions that usually only exist in the most extreme environments can be recreated on Earth, helping scientists better understand the nature of the universe.

DIFFERENT TYPES