Distributed fiber-optic sensors are widely used to monitor temperature and strain in infrastructure, but their spatial resolution has long been limited. In a new study, researchers from Shibaura Institute of Technology and Yokohama National University, Japan, have demonstrated that operating near a previously avoided frequency regime and suppressing signal distortions allows reflection-based sensing to achieve a world-record spatial resolution of 6 mm among single-end-access configurations. This enables precise monitoring of temperature and strain in infrastructure.

Distributed fiber-optic sensing technologies play a crucial role in monitoring temperature and strain across large structures such as bridges, tunnels, pipelines, and buildings. Unlike conventional point sensors, distributed fiber-optic sensors provide continuous measurements along their entire length, allowing early detection of damage or abnormal conditions. However, one persistent challenge has been spatial resolution—the ability to pinpoint exactly where a change occurs. Improving resolution without complicating system design has remained a central goal in fiber-optic sensing research.

One promising technique, known as Brillouin optical correlation-domain reflectometry (BOCDR), enables distributed sensing using light injected from only one end of the fiber. This reflection-based configuration simplifies installation and allows measurements even if the fiber is damaged. BOCDR also offers higher spatial resolution than many other Brillouin-based methods. Yet, its performance has been constrained by a widely accepted assumption: operating near or beyond the Brillouin bandwidth, a frequency range intrinsic to the fiber, was believed to cause unstable signals and unreliable measurements. As a result, this operating regime has largely been avoided, limiting achievable resolution.

Electrons have three intrinsic properties: spin, charge and orbital angular momentum. Researchers have long studied how to use spin to more efficiently create an electrical current. But the field of orbitronics—which is based upon using an electron’s orbital angular momentum, rather than its spin, to create a current flow—remains relatively new.

“Traditionally, it has been technically challenging to generate orbital current,” says Dali Sun, a professor of physics and member of the Organic and Carbon Electronics Lab (ORaCEL) at NC State University.

In a recent study, however, Sun and an international team of researchers demonstrated a groundbreaking new method to generate orbital current.

A newly developed fiber-optic microphone demonstrates how light-based sensing can overcome the limitations of conventional electronics in extreme environments.