Did these French physicists just find a way to harness atomic ‘dark states’ to store light?

They have discovered this phenomenon by a process called subradiance.

Did these French physicists just find a way to harness atomic 'dark states' to store light?
This is the first time that scientists have observed this phenomenon called subradiance. (Picture credits: Physics World)

Laws of quantum physics state that every particle strives to gain a neutral state. Noble gases like Helium and Argon are the only stable elements. Every element in the world wants to become like them. Hence, excited particles cannot be sustained in nature. But, a team of physicists have achieved a breakthrough by a phenomenon called subradiance. Through this process, they were able to sustain an ensemble of excited atoms. This phenomenon can enable scientists to store and release light on demand. The researchers believe that their findings will aid the development of a wide range of new technologies. This can prove to help develop new quantum computers and precise weather prediction sensors. The findings were published in the journal Physical Review X on May 10th.

It is for the first time that physicists have produced this phenomenon, known as subradiance. In this process, atoms in a dense cloud of atoms linger in an excited state. According to this new study, harnessing subradiance could allow scientists to establish stable, long-lasting quantum networks from clouds of atoms.

Photons, or light particles, absorb energy from atoms. This causes electrons to jump from the lowest-energy, or ground state, to higher-energy, or excited states. When atoms are stimulated, they spontaneously emit a photon to return to their ground state. However, this is not always the case. When many atoms are packed together, the light they emit cancels out, and the atoms remain excited. For this phenomena to happen, atoms should be separated by a distance shorter than the wavelength of the produced photon.

The breakthrough was achieved by a team of French physicists. These included: Giovanni Ferioli, Antoine Glicenstein, Loic Henriet, Igor Ferrier-Barbut and Antoine Browaeys. The researchers utilized an ensemble of ultracold Rubidium atoms. They excited the Rubidium atoms by using a resonant laser. This enabled them to store light in the cloud of Rubidium atoms. The researchers then used a second laser to turn off the atoms’ interactions and release the light that had been trapped.

In order to examine the properties of clouds, the team created several clouds of varying forms and sizes. They also found that the number of atoms in an excited cloud affected its longevity. This means that the more atoms in the cloud, the longer it took them to return to their ground states. The team will try to further experiment with arranging these clouds in geometric forms. This would further enhance the longevity of these clouds.