Scientists built a machine that breaks the normal rules of light

It could open doors to new quantum technologies and telecoms systems.


Researchers from the National Physical Laboratory (NPL) have investigated how light can be controlled in an optical ring resonator, a tiny device that can store extremely high light intensities. Just as certain ‘whispers’ can travel around a whispering gallery and be heard the other side, in an optical ring resonator wavelength of light resonate around the device.

This is the first study that uses optical ring resonators to detect the exchange of two sorts of unconstrained symmetry breaking. By investigating how the time between beats of light changed and how the light is polarized, the group has been capable uncover better approaches to control light.

Light usually follows time-reversal symmetry, means, if time is reversed, the light should travel back to its origin. According to this study, at high light intensities, this symmetry is broken within optical ring resonators.

Researchers noted this could be used to combine and rearrange optical pulses, for example in telecommunication networks.

During experiments, researchers also showed that light can suddenly change its polarization in ring resonators. This is as though a guitar string was at first culled in the vertical course yet all of a sudden begins to vibrate either in a clockwise or an anticlockwise circular movement.

Francois Copie, a scientist on the project, explains: “When seeding the ring resonator with short pulses, the circulating pulses within the resonator will either arrive before or after the seed pulse but never at the same time.”

“This has not only improved our understanding of nonlinear dynamics in photonics, helping to guide the development of better optical ring resonators for future applications (such as in atomic clocks for precise time-keeping) but will help scientists to better understand how we can manipulate light in photonic circuits in sensors and quantum technologies.”

Pascal Del’Haye, Senior Research Scientist, NPL, said: “Optics have become an important part of our telecoms networks and computing systems. Understanding how we can manipulate light in photonic circuits will help to unlock a whole host of new technologies, including better sensors and new quantum capabilities, which will become ever more important in our everyday lives.”

The study is published in the Physical Review Letters.


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