Successfully fabricated a diamond mirror that can withstand the power of a 10kW . laser

A new high-strength mirror made entirely of diamond could be used in semiconductor manufacturing and deep space communication.

A team at the Harvard John A. Paulson School of Engineering and Applied Science (SEAS) has built a superstrong mirror from diamond that harnesses the power of a high-powered continuous wave (CW) laser. The new study was published in the journal Nature Communications on May 11.

Illustration of a high power CW laser beam hitting nanostructures on a diamond mirror.

High-powered lasers play an essential role in the production of most cars, trains, and airplanes. However, building durable devices to control these powerful lasers capable of cutting through steel is extremely difficult.

Today, most mirrors used to direct CW laser beams are made by layering thin layers of materials with different optical properties. A very small error in one of these layers will cause the powerful laser to burn through the materials, damaging the system.

The SEAS team made a new mirror entirely out of diamond. This greatly reduces the chance of error as it is made of only one material, and greatly increases the life of the mirror thanks to the strength of the material.

"Our 'single-material' mirror technology eliminates the thermal stress problems that plague conventional mirrors (which are made of multiple layers of material) when irradiated with high optical power. This promises to improve or create new applications for high-power lasers," said Professor Marko Loncar at SEAS, a member of the research team.

The team of experts said that the diamond mirror withstood tests with a 10 kW laser without any damage. The technique for the new mirror was originally designed to etch nanostructures into diamond, for use in the field of quantum optics. The team used this method to engrave small tee-shaped columns (the accessory used to place the ball in golf) onto the surface of a 3mm x 3mm diamond piece. They chose the tee because it makes the diamond surface 98.9% reflective.

"It's remarkable that we've focused a 10 kW laser focused on a 750 micrometer wide spot on a 3mm x 3mm diamond piece, which means a lot of energy is concentrated on a tiny spot, and we still don't get it. burn it. This is important because as laser systems become more and more power hungry, you need to find ways to make the optics more powerful," said Haig Atikian, PhD student at SEAS, member of the research team, said.

Experts hope that in the future, the new type of mirror can be used in semiconductor manufacturing, defense, deep space communication and many other applications.