Discovery poised to help detect dark matter and pave the way to unravel the universe’s secrets

Light waves normally travel in straight lines — reflecting off mirrors, bending through water, and following the familiar rules of electrodynamics that power our modern world.

Now, a team led by Professor Baile Zhang at NTU Singapore has gone beyond these conventions. Writing in Science, they report having created a special medium where light travels in one direction only, darting along complex three-dimensional zig-zag paths without reflecting off obstacles. This strange behavior simulates an exotic form of physics known as axion electrodynamics — the same interaction thought to involve axions, mysterious particles that may make up dark matter.

The result? A new class of material called a Photonic Axion Insulator, where light behaves unlike anything we see in nature.

“It’s as if the light acts like the Flash running in a zig-zag pattern,” — Dr Guigeng Liu, Research Fellow and first author of the study

Read more: Discovery poised to help detect dark matter and unravel the universe’s secrets 
Published in Science (10 Jan 2025) — “Photonic Axion Insulator”