Quantum Diamonds Emit Light in Custom-Made Shapes

Controlling the light from individual quantum emitters—tiny sources that release one photon at a time—is a central goal for developing advanced quantum technologies. Conventional methods struggle to shape this light at its origin, limiting our control. Now, researchers have pioneered a new technique for generating arbitrarily structured light directly from individual nanodiamonds.

The method involves integrating a nanodiamond containing a light-emitting defect, known as a nitrogen-vacancy centre, with a specially designed holographic metasurface. This nanoscale surface acts like a microscopic mould, encoding complex wavefront information onto the photons as they are released. The team demonstrated this precise, at-source control by coaxing the nanodiamonds to emit light in the shape of triangles and even letters.

This ability to freely structure photon emission at its source offers new degrees of freedom for optical information processing. It holds great promise for creating scalable, high-capacity quantum nanophotonic devices, potentially revolutionising areas like single-photon encryption and recognition.