Physicists Say They've Built an Atom Laser That Can Run 'Forever'

Physicists have been able to create a beam of atoms that behaves the same way as a laser and that can stay on forever.

It is possible that the technology is on its way to practical application.

This is a huge step forward for what is known as a "atom laser", a beam made of atoms that could one day be used for testing fundamental physical constants, and engineering precision technology.

The lasers have been in use for a while. The first atom laser was created in 1996. A laser made of atoms would need their own wave-like nature to align before being shuffled out as a beam.

It is easier to think about than it is to actually think about it. There is a Bose-Einstein condensate at the root of the atom laser.

A cloud of bosons is cooled to a point above absolute zero. The atoms sink to their lowest possible energy state.

When they reach these low energies, the particles' quantum properties can no longer interfere with each other, and they move close enough to each other to form a high density cloud of atoms.

BECs are a bit of a contradiction. Light can destroy a BEC.

Scientists have been able to achieve atom lasers that are pulsed, rather than continuous, and involve firing off just one pulse before a new BEC needs to be created.

A group of researchers at the University of Amsterdam decided something needed to change in order to create a continuous BEC.

The gradual cooling of atoms was done in one place. In our setup, we decided to spread the cooling steps not over time, but in space.

Ultracold atoms arrive at the center of the experiment, where they can be used to make waves. New atoms are on their way to replenish the bec. We can continue the process in this way.

The 'heart of the experiment' is a trap that prevents the BEC from being exposed to light.

It was easier to protect the BEC from the light produced by the cooling laser than it was in the past. There were also bureaucratic and administrative obstacles.

"On moving to Amsterdam, we began with a leap of faith, borrowed funds, an empty room, and a team entirely funded by personal grants," said physicist Chun-Chia Chen.

The experiment was on the verge of working in the early hours of Christmas morning. We added an extra laser beam to solve a technical problem, and every image we took showed the first continuous- wave BEC.

The next step is to maintain a stable atom beam after the first part of the laser has been realized. Transferring the atoms to an untrapped state could be done to extract a propagating matter wave.

The prospect opens exciting opportunities because they used strontium atoms. If atom interferometry using strontium BECs is used, it could be used to investigate Einstein's theory of relativity.

The researchers wrote in their paper that their experiment is an analogue of a continuous- wave optical laser.

This proof-of-principle demonstration provides a missing piece of atom optics that can be used to build continuous coherent-matter-wave devices.

The research was published in a journal.