A special laser (red) can bend electrons (blue) into a spiral shape
Dr. Yiqi Fan (University of Konstanz)
With the help of a laser, the electrons were transformed into spiral waves of mass and charge.
“Chirality, or handedness, is an intriguing and still partially mysterious feature of our universe.” Peter Baum Researchers at the University of Konstanz in Germany have discovered that chiral objects, like coils or L-shaped blocks, can be either left- or right-handed, but non-chiral objects, like circles or lines, cannot. Many molecules and materials are inherently chiral, and their function changes depending on whether they are right- or left-handed. But Baum and his colleagues have devised a way to impart chirality to something very small and fundamental: a single electron.
Because electrons are quantum objects, they exhibit both particle-like and wave-like behavior, depending on the experiment. In this experiment, the researchers exploited the wave nature of electrons. First, they create a very fast pulse of electrons and pass it through a thin ceramic membrane. There, the particles encounter a special laser beam. The beam is shaped like a light vortex and, as a result, carries a similarly shaped electromagnetic field. This electromagnetic field affects the wave function, or wave properties, of each electron that passes through it.
Finally, the researchers detected these manipulated electrons and calculated the “expectation values” of each of their masses and charges — that is, the places in space where both properties are most likely to be measured in non-zero quantities. These regions of space formed the shape of a three-dimensional coil, with clearly marked left- or right-handed winding.
Ben McMorran The University of Oregon researchers have previously experimented with making coils of chiral electrons, and they say their new work “represents a very advanced advancement in the state of the art of shaping electrons.” They have demonstrated precise control over the spiraling electrons, which they say will be crucial for using the particles in applications such as imaging and controlling existing materials.
Baum and his colleagues have already found that shining a left-handed coil of electrons at right-handed gold nanostructures results in different ricochet patterns than shining it on left-handed structures, opening up the possibility of using such coils to selectively affect chiral moieties in chemical compounds or electronic devices.
Having created these strange electrons in the lab, Baum says he’s now interested in whether they could arise independently in nature: “We’re starting to explore these possibilities.”
topic:
