How big is the world’s most powerful laser?

At least 60 times more powerful than its predecessors, the laser at the National Ignition Facility (NIF) in California is an impressive feat of engineering. It contains the largest optical instrument ever built, 7,500 fl ash-lamps, 97 kilometres (60 miles) of mirrors and fi bre optics, and is the size of three football pitches. At the master oscillator of the NIF, a low-energy pulse of photons is generated using an optical fi bre laser. To amplify the laser pulse it is broken down into 192 separate beams; these are then carried through fi bre-optic cables to a series of amplifi ers. The combined power of all 192 beams heats the target to 100 million degrees Celsius (180 million degrees Fahrenheit) – more than six times hotter than the core of the Sun – and puts it under a force exceeding 100 billion atmospheres, all in less than a second.