Electrons in a magnetic field can pull off neat tricks like discrete energy levels and the quantum Hall effect. Light, being neutral, usually sits this one out. That has long stymied efforts to reproduce such effects in optical systems, especially at the high frequencies used in today’s comms kit.

Now researchers at Shanghai Jiao Tong University and Sun Yat-Sen University say they’ve cooked up a way to generate pseudomagnetic fields inside photonic crystals. Their work has just been published in Advanced Photonics, which we get for the crossword.

Instead of real magnetism, the team tweaked the symmetry of silicon photonic crystal units. By changing how asymmetric each tiny element was, they could impose artificial gauge fields with arbitrary spatial patterns. They managed this without breaking time-reversal symmetry which means that they don't have to worry about messages arriving before they are sent (unless we have gotten it wrong which we might have).

To prove it wasn’t just theory, they built two bread-and-butter integrated optics components. One was an S-shaped waveguide bend that shifted light around corners with less than 1.83 decibels of loss. The other was a power splitter that carved light into two equal paths with little extra loss and barely any imbalance.

The kit used standard telecoms modulation, the devices carried a data stream at 140 gigabits per second. That suggests the pseudomagnetic field approach plays nicely with existing fibre comms systems.

Beyond the obvious comms angle, the researchers claim this opens doors for optical computing, quantum information and other exotic tech. More importantly, it gives physicists a playground to test how neutral particles might behave when tricked into thinking they are in a magnetic field.