Twisting light with 2D semiconductors
University of Melbourne researchers and collaborators at Hanyang University in South Korea have discovered a new way to create ‘light twisters,’ or spiralling whirlpools of light, using van der Waals (vDW) 2D compound semiconductors MoS2 and hexagonal BN.
Published in the journal Light: Science and Applications, the development could improve speed, cost and security in optical communications, according to the team.
Until now, creating such twisters required bulky and expensive technology. In this work, the researchers used an 8 µm-thick hexagonal hBN crystal for the creation of optical vortices carrying topological charges of ±2. They also presented the generation of an optical vortex beam in a 320 nm-thick MoS2 crystal with a conversion efficiency of 0.09.
Melbourne University PhD student Sujeong Byun said the process could be a game-changer for wide-scale optical communications. “Because of the spiral structure, the light twisters offer an additional dimension for encoding information. Like the construction of extra lanes on a data highway, it would allow more information to travel at once,” she said.
“We found that when circularly-polarised light, – where all the light particles (photons) spin in the same direction – enters the vdW material, the direction of its spin flips, and it gains a spiral twist, turning it into an optical vortex, or whirlpool of light.”
“Until now, some researchers have speculated on the potential of this material to twist light this way. Now, we have achieved it experimentally for the first time.”
Byun's supervisor Sejeong Kim added: “Many researchers are working to advance optical communications to overcome speed and security challenges. By ‘twisting light’ through beams, optical networks could potentially store up to 50 times more data than existing networks. By using different ‘twists,’ multiple bits of information could be encoded on a single photon, or light particle – significantly increasing overall data capacity.
“With our solution, it becomes possible to create a tiny device, at the on-chip scale, that will allow fibre optics communication to increase bandwidth, which is very exciting for the industry. It offers the prospect of smaller, cheaper and more scalable optical devices that could be integrated into future communication systems, including satellites.”
The team is now working to make the process compatible with existing communications technologies and exploring how the technology can be integrated into larger optical systems.
Reference
Jo, J., Byun, S., Bae, M. et al. Light Sci Appl 14, 277 (2025)
