Researchers from NorthWestern and Columbia Universities have developed a nanolaser with potential to aid towards the treatment of neurological disorders or detect disease biomarkers.

The laser, which is designed to be approximately 1 / 1,000th the thickness of a single human hair, can fit and function within living tissues without any negative impact.

It is made of glass, therefore biocompatible, for use with longer and shorter wavelengths of light. Also, it can operate in confined spaces, added the team.

Northwestern University researcher Teri Odom said: “Longer wavelengths of light are needed for bioimaging because they can penetrate farther into tissues than visible wavelength photons.

“But shorter wavelengths of light are often desirable at those same deep areas. We have designed an optically clean system that can effectively deliver visible laser light at penetration depths accessible to longer wavelengths.”

Nanolasers are typically considered less efficient than macroscopic lasers, while also requiring shorter wavelengths, such as ultraviolet light, which could cause damage.

For the nanolaser platform, the team used photon upconversion, which involves absorption of low-energy photons and formation of a single photon with higher energy.

Researchers upconverted low-energy infrared photons into visible laser beams, allowing the use of the laser under low powers.

Columbia University School of Engineering researcher James Schuck said: “Our nanolaser is transparent but can generate visible photons when optically pumped with light our eyes cannot see.

“The continuous wave, low-power characteristics will open numerous new applications, especially in biological imaging. Excitingly, our tiny lasers operate at powers that are orders of magnitude smaller than observed in any existing lasers.”

The National Science Foundation, US Department of Defense and US Department of Energy supported the project.