In the world of high-powered lasers, a new kid is on the block. And it’s damn powerful! The Berkeley Lab Laser Accelerator (BELLA) has developed a laser which can deliver a huge 1 petawatt of power in a single pulse which lasts for 40 femtoseconds. It can do this once every second, making it a one-pulse-per-second laser.
Now, what do those terms with the funny units mean?
A petawatt is a million billion watts – a quadrillion watts, in everyday language. And a femtosecond is a quadrillionth of a second – one part of 1015 parts in a second! No other laser in the world has this high a peak power and still function at that high a pulse rate (1 pulse per second). This is now officially a world record – this is the world’s most powerful laser.
Building an accelerator
Enter the Laser and Optical Accelerator Systems Integrated Studies (LOASIS) program and there is where BELLA really scores. The really powerful laser is a prototype for the ultimate laser that will be built to accelerate particles for an accelerator. This accelerator will use the laser’s energy to speed up electrons and protons.
Conventional particle accelerators, the LHC included, uses electric fields to accelerate the charged particles, while magnetic fields bend them. The laser uses its intense heat to generate plasma. This plasma has a lot of free electrons swimming around and they can absorb energy and be accelerated to very high speeds. The trick is to make all of these electrons accelerate in phase.
Says Wim Leemans of Berkeley Labs Accelerator and Fusion Research Division (AFRD), the dept. responsible for the construction and maintenance of the LOASIS:
BELLA will be an exceptional tool for advancing the physics of laser and matter interactions. The laser’s peak power will give us access to new regimes, such as developing compact particle accelerators for high-energy physics, and tabletop free electron lasers for investigating materials and biological systems.
BELLA laser will be used to build the world’s first plasma accelerator, which will be able to accelerate electrons to 10 GeV. This is about a thousandths of what the LHC produced, but it’s still very high energy achieved on a device a millionth of the size of the LHC. This successful preliminary test of the BELLA laser was part of the LOASIS test which is due to start this autumn.