'Quantum Whirlpool' Created From Spiral Laser Beam Could Lead To Development Of Promising New Technologies

Researchers created a spiral laser beam that can spawn a whirlpool of hybrid light-matter particles.

The particles, dubbed polaritons, are remarkable hybrid particles that have the properties of both matter and light, Australian National University reported. Harnessing the ability to control these particles could help lead to the development of new technologies that sync up conventional electronics with laser and fiber-based technologies.

"Creating circulating currents of polaritons - vortices - and controlling them has been a long-standing challenge," said leader of the team, theoretician Elena Ostrovskaya, from the Research School of Physics and Engineering. "We can now create a circulating flow of these hybrid particles and sustain it for hours."

Polaritons form in semiconductors when laser light interacts with electrons and positively charged vacancies in a way in which light can no longer be distinguished from matter. To create the spiral beam the researchers created a piece of brass containing patterns of holes that increased in size. The team then directed the laser into a semiconductor microcavity.

"By using a spiral mask to structure our laser, we create a chiral system that prefers one flow direction. Therefore we can create a single, stable vortex at will," said project leader Robert Dall.

The vortices demonstrate quantum fluid behavior, and in this state polaritons coalesce into what is known of as a Bose-Einstein condensate.

"As well as being a window into the quantum world, these polaritonic vortices could be used to construct extremely sensitive detectors of electromagnetic fields, similar to SQUIDS (Superconducting QUantum Interference Devices)," Ostrovskaya said.

The polaritonic vortices could also be used as effective quantum information carriers. The researchers hope their success will inspire other research teams keep making steps forwards in this field.

"Polaritonics is a rapidly developing research field all around the world. We hope we can build a network of groups researching these devices across Australia and joining the international effort," Ostrovskaya concluded.

The findings were published in a recent edition of the journal Physical Review Letters.

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