A diamond is illuminated with a green laser

A green laser illuminates a diamond inside a sapphire ring to generate a maser. Credit: Jonathan Breeze

Applied physics

Diamonds and sapphires help to revive an obscure technology

Medical sensing and security could benefit from a retooled version of the laser’s older sibling.

By shining light into a diamond, scientists might be able to resurrect the laser’s older sibling: the maser.

Masers were the forerunners of lasers, emitting microwaves instead of light. They are used as timekeepers in atomic clocks and to boost radio signals from spacecraft. But they have few other applications because they need freezing temperatures and vacuum conditions to operate.

To create a more practical maser, Jonathan Breeze at Imperial College London and his colleagues started with defective diamonds, in which some of the gem’s usual carbon atoms were replaced with nitrogen. The researchers inserted a diamond into a ring of sapphire and put the ensemble in a magnetic field. The researchers then used laser pulses to excite electrons in one of the gem’s defective sections. This coaxed the diamond into emitting continuous microwaves at room temperature for more than ten hours.

Room-temperature masers could be used for medical sensing, security and emerging quantum technologies, the authors say.

See related News & Views: A diamond age of masers