BELLA (laser)

The Berkeley Lab Laser Accelerator or BELLA is a laser built by the Thales Group and owned and operated by the Lawrence Berkeley National Laboratory.[1][2] On 20 July 2012 BELLA fired a 40 femtosecond laser pulse, establishing a world record for most powerful laser.[2][3]

BELLA was designed and built by Thales as part of the Laser and Optical Accelerator Systems Integrated Studies (LOASIS) program at LBNL. The LOASIS group studies the application of high-powered lasers to build compact particle accelerators. The BELLA laser was developed for the purposes of studying this principle.[2][3] The idea is that a laser which delivers a large amount of power in a very short pulse can cause ionization in a gas followed by plasma oscillation.[3] As a result the gas will emit electron bundles which can be used for medical imaging or materials research.[2][3]

On 20 July 2012, BELLA fired a laser pulse with a duration of 40 femtoseconds and a repetition frequency of 1 hertz. The pulses had a compressed output energy of 42.2 joule, making the power output of the laser 1 petawatt:

${\displaystyle {42.2J \over 40fs}={42.2J \over 40*10^{-15}s}\approx 1*10^{15}J/s=1PW}$

This result established BELLA as the highest peak power laser in the world (at a 1 Hz repetition rate).[1][2][3]

In December, 2014, a team of researchers accelerated electrons using BELLA up to an energy of 4.25 GeV—the absolute highest energies recorded to date using a compact accelerator.[4]