The National Ignition Facility has broken the record for the most powerful laser beam ever produced: 500 terawatts, or half a petawatt. 500 trillion watts in certainly a lot of power, but the huge numbers are really the result of the tiny area of effect: 2 millimeteres. The scientiscts focused 1.86 million Joules on this area, producing the huge wattage rating.
Why does anyone want a laser this powerful? Given that it is built into a building and has to be incredibly precisely aligned, it is useless as a weapon. That makes it of little value to mad scientists. Instead, this laser system (it is a collection of beams, rather than one) will be used to examine materials under extreme conditions. This system is capable of simulating the incredible forces at work in the interior of stars, which allows experiments to take place about such environments, instead of just conjecture.
The laser may also be useful for fusion research. The system is capable of generating sufficient pressures to collapse a deuterium pellet to the point where fusion occurs. As controlled fusion reactions are the holy grail of energy production, the prize is great indeed.