If you’ve ever tried to photograph a soccer match, you know that you have to use a short shutter speed to freeze the movement of the players and the ball. The picture should probably be taken within a millisecond.
The faster something moves, the shorter the shutter speed must be for the image to be sharp.
Not only are electrons small, but they also move incredibly fast. In the smallest atom, hydrogen, one electron orbits around the nucleus. The cycle time in the outermost lane is a blitz 0,000,000,000,000,000.15 seconds.
Put another way: 150 x 10-18 second, or 150 attoseconds, which gave rise to a new branch of science: attosecond physics.
Laser tricks
Light, which travels at about 300,000 kilometers per second, takes about one attosecond to pass an atom.
To study how electrons move in atoms and molecules, an international group of researchers used lasers that emit light in short pulses.
– There are no lasers with short enough pulses, so we have to use some tricks, says Antoine Camber, a researcher at UiO.
The technique he and his colleagues are using involves directing ultrashort but high-energy laser pulses at the gas molecules they want to study, in this case nitrogen and carbon dioxide.2.
Electrons surf on a laser wave
The laser pulse gives some of the electrons enough energy for them to leave the molecule they are bound to. The electrons surf for a while on the laser wave before being picked up by the molecule again.
When the electrons return to the molecule, they emit light of a very short wavelength, typically between 10 and 100 nanometers, encoded by the state of the molecule.
– We record flashes of light every few hundred attoseconds, says Camper. It’s short enough that the glimpses give an insight into the molecules’ inner lives.
Each flash of light provides a snapshot of the molecule, like a frame on a movie.
In a way, we’re manipulating the electrons to make themselves appear, says Camper.
They conducted the experiments at the CELIA laboratory in Bordeaux, France.
With our method, we can study the electron’s motions twice as often as before, says Kamper.
Too short for Tiktok, long enough for quantum tech
Film length increased to – Not a flash! – 3 femtoseconds, or 0,000,000,000,000,003 seconds.
Although it would be a very short film even for Tiktok, it is actually long enough to say something about the dynamics within molecules.
Ultrafast measurements provide new opportunities for understanding processes at a quantum level and for researchers in this field Already working on applications in electronics, quantum technology, and biomedicine.
The article was first published on Titan.uio.no
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