Scientists want to rip the Universe apart. At least that is what a Daily Mail headline might read. Lasers can now reach power in the petawatt range. And, when you focus a laser beam that powerful, nothing survives: all matter is shredded, leaving only electrons and nuclei.
But laser physicists haven’t stopped there. Under good experimental conditions, the very fabric of space and time are torn asunder, testing quantum electrodynamics to destruction. And a new mirror may be all we need to get there.
On average, the amount of power used by humans is about 18 terawatts. A petawatt is 1,000 times larger than a terawatt. The baddest laser on the planet (currently) produces somewhere between 5 and 10 petawatts, and there are plans on the drawing board to reach 100 petawatts in the near future. The trick is that the power is not available all the time. Each of these lasers produces somewhere between 5-5000 J of energy for a very very short time (between a picosecond—10-12s—and a few femtoseconds—10-15s). During that instant, however, the power flow is immense.
The numbers get even more mind blowing when you consider that all of that energy is focused, such that the intensities reach something like 1022W/cm2. To put this in perspective, you start creating a plasma when intensities hit 1012W/cm2. Once intensities get above 1025W/cm2, if the light hits just a single electron, there's enough energy to start a cascade of electron-positron production out of the vacuum. If the laser intensity hits 1029W/cm2, not even that single electron is required—the light will rip virtual electrons out of the vacuum, generating real charges from the apparent nothingness of empty space.
But getting to 1025W/cm2 is tough. The issue is one of material. Or, rather it's the lack of a material that can survive long enough to focus the laser light. This is where plasma mirrors come in.
...
