Scientists have created the first microlasers capable of detecting individual molecules and even single atomic ions, a breakthrough that could significantly advance early disease diagnosis and molecular-scale medical testing. Researchers at the University of Exeter’s Living Systems Institute have published their work in Nature Photonics. The paper opens up new possibilities for microlaser biosensing technology, including “lab-on-a-chip” technology capable of instant medical testing and diagnosis.

Microlasers are tiny glass beads measuring around just 0.1 mm (the width of a human hair) to 0.01 mm (the length of a single bacterium). With a central cavity that acts as a tiny mirror, they emit and bounce light in a circular motion around the bead. This circular path of trapped light is known as whispering gallery modes (WGM) laser technology.

Light continuously circulates around the sphere’s inner boundary, enabling the device to detect extremely small disturbances on its surface. Previous research has shown that such microlasers can even be inserted into living cells, acting as optical barcodes to track cellular movement inside organisms.