A new breakthrough has allowed physicists to create a beam of atoms that behaves in the same way as a laser and could theoretically last “forever.”
This may finally mean that the technology is on its way to practical application, although there are still significant limitations.
However, this is a huge step forward in what is known as the “atomic laser” – a single wave beam made of atoms that can one day be used to test fundamental physical constants and microengineering technologies.
The corn laser has been around for a minute. The first atomic laser was created by a team of MIT Physicists in 1996. The concept seems quite simple: just as traditional light-based lasers consist of photons that move in sync with their waves, atoms-made lasers require their undulating nature. to align before mixing as a beam.
However, as with many things in science, it is easier to visualize concepts than to perceive them. At the root of the laser atom is a state of matter called the Bose-Einstein capacitor BEC.
BEC is generated by cooling the cloud of bosons to just one part above absolute zero. At such low temperatures, the atoms sink to the lowest possible energy state without stopping completely.
When they reach these low energies, the quantum properties of the particles cannot interfere with each other; They get close enough together to cause some kind of disturbance, resulting in a cloud of high-density atoms that behaves like a single “super atom” or wave of matter.
However, BECs are a bit of a contradiction. She is very fragile. Even light can destroy BEC. Given that the atoms in BEC are cooled by an optical laser, this usually means that BEC is ephemeral.
The atomic laser that scientists have been able to achieve so far has been pulsed, not universal; This involves only one pulse that is triggered before a new BEC has to be created.
To create a continuous BEC, a team of researchers from the University of Amsterdam in the Netherlands realized that something needed to change.
“In previous experiments, the gradual cooling of atoms took place in one place. In our setting, we decided to spread the cooling steps not in time but in space: we make the atoms move as they progress through successive cooling steps, ”explained physicist Florian Shrek.
“Eventually, the ultra-cold atoms reached the heart of the experiment, where they could be used to form coherent waves of matter in BEC. But by the time they use these atoms, the new atoms are about to fill the BEC. That way we can continue the process – essentially forever. “
This “heart of the experiment” is the trap that protects the BEC from light, a tank that can be continuously filled during the experiment.
However, protecting BEC from light from cooling lasers, although simple in theory, was again more difficult in practice. There were not only technical obstacles, but also bureaucratic and administrative obstacles.
“When we moved to Amsterdam in 2013, we started with a leap of faith, borrowed money, an empty room and a fully funded team of personal subsidies,” said physicist Chun Chia-chen, who leads the search.
“Six years later, in the early hours of Christmas morning 2019, the experiment was finally on par. We had the idea to add an extra laser beam to solve one last technical problem and immediately every photo we took showed BEC, the first continuous wave of BEC.
Now that the first part of the continuous atomic laser – the “continuous atom” part – has been achieved, the team said the next step is to maintain a constant atomic beam. They can achieve this by moving the atoms to an unlimited state, thus extracting a wave of diffuse matter.
They said they used strontium atoms, a popular choice for BEC, an opportunity that opens up exciting possibilities. Atomic interferometry with strontium BEC can be used, for example, to conduct research in relativity and quantum mechanics or to detect gravitational waves.
“Our experiment is analogous to the material wave of a continuous-wave optical laser with fully reflective mirror cavities,” the researchers wrote in their paper.
“This demonstration to prove the principle provides a hitherto missing new part of atomic optics, allowing the construction of coherent devices with continuous waves.
The search is published in temperamental nature.
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