For over 100
years we have well-known that matter and energy are interchangeable. The advancement
of nuclear power has revealed that matter can be converted into energy, but
converting energy into matter has thus far proven a lot more challenging.
The battleground
for such an accomplishment is at the end of the most powerful lasers ever anticipated,
currently being planned and assembled in a number of different countries. Three
projects top the “one to watch list” of the laser world, organized by the
journal Science. They are China’s Station of Extreme Light (SEL), Russia’s
Exawatt Center for Extreme Light Studies (XCELS), and the Department of
Energy’s Optical Parametric Amplifier Line (OPAL).
These
three lasers are scheduled to entirely annihilate the current record for laser
power, which is 5.3 million billion watts or 5.3 petawatts (PW) and achieved by
Ruxin Li and colleagues at the Shanghai Superintense Ultrafast Laser Facility
(SULF). Li is also behind SEL and is optimistic that by 2023 his team of
researchers could reach the goal of a 100-PW laser.
The
Russian instrument is still in the design stage of development but is more audacious
in its target. The scientists hope it will accomplish 180 PW. Both SEL and
XCELS are likely to work on the same principle. They bombard a series of pulses
(four 30-PW pulses for SEL and a dozen 15-PW pulses for XCELS) and combine them
into a particular extra-powerful one.
Science Mag reports that this method requires extreme accuracy and even the slightest
vibration or temperature variation can compromise the accomplishments of such a
powerful laser pulse. For this purpose, OPAL is going a different way. It is projected
to reach 75 PW with a single pulse.
There are
other facilities working on “more modest” equipment that will target to deliver
30-PW machines and SULF itself believes to break the 10-PW record this year.
High-energy is required but it is not the only requirement to “break the
vacuum” and turn photons into electrons and positrons, their antimatter complements.
The way
that SEL is expected to do this is very exciting. The laser will hit a helium
target and release electrons. Some of the photons from the beam will rebound
off the electrons and then collide with other photons, creating
particle-antiparticle pairs.
If SEL can
really break the vacuum, it could change the way we approach particle physics.
Traditional particle accelerators might be changed for faster and cheaper
laser-powered ones.
Reference: | Science Mag |
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