Laser turns solids into invisible

A laser beam illuminating a unique snake made the material almost disappear. The effect occurs at infrared wavelengths, so the naked eye can not be observed.

However, team member Chris Phillips, " If this effect occurs at the wavelengths seen for the molecules that make up your hand, then when this laser beam hits you, your hands will become stronger," says a physicist at Imperial College London. transparent ".

" And if you then strengthen the laser beam a little bit, the sighting through the back of the hand will become brighter, thanks to the magnifying effect of the light in the beam ," he said.

Phillips and colleagues from the University of Neuchâtel, Switzerland, believe that this method may someday be applied to light at visible wavelengths, and lead to new technologies that help look through debris in search. Search for victims of catastrophes, or observe the internal organs of the body that are covered by bones.

In a report recently published in the journal Nature Materials, scientists say they have done their job on materials that are used to make semiconductor chips. Often, the electrons in the atoms of this material interact with the light beams in a peaceful way.

But Phillips and his associates have re-arranged the material so that it contains artificial atoms - specially structured crystals that are only a few billionths of a meter in length. Because these atoms are artificial, scientists can manipulate the behavior of electrons - which are characteristic of waves - in them.

When the light beams onto the material, it interacts with the state of the electron waveforms within the artificial atoms, so they cancel each other and create a new, transparent, half-material form. wave.

Scientists continue to amplify the beam, though 80% of the artificial atoms are in a state of low excitation. This goes against a theory proposed by Albert Einstein, that to amplify light in a laser beam, most atoms must be in a highly excited state.

" They have demonstrated that this effect can occur in solid state environments, which are important for practical applications ," said Lene Vestergaard Hau, associate professor of applied physics at Harvard University. .

The team's next goal was to better control and amplify the beam, so that no special structure could be created that could produce a solid-state viewing effect.

T. An