Toward a new generation of light-emitting metasurfaces

Producing organized, directed light can be a challenge. Lasers generate coherent light beams with stimulated photon emission, but for spontaneous emission sources, the light is isotropic and can only be controlled with a combination of lenses, filters, polarizers, and diaphragms. These add bulk and expense to any device that uses them, and they are an inefficient way to solve this problem: Most of these components work by discarding unwanted light.

Jean-Jacques Greffet and Benjamin Vest explored the potential for creating light-emitting metasurfaces that simultaneously control light frequency, direction, and polarization. Such materials can combine light generation and manipulation into a thin device that can be miniaturized and incorporated into cell phones, virtual reality headsets, and other electronic devices.

The duo discussed different strategies for creating light-emitting metasurfaces, including heated surfaces that emit infrared light via blackbody radiation.

“Achieving the possibility of metasurfaces emitting light has already been demonstrated for incandescent sources, which we call thermal metasurfaces,” said Greffet. “The next step is to extend that to photoluminescent or electroluminescent devices.”

In the electroluminescent approach, the authors described a potential implementation using quantum dots as a light source, exciting a surface wave that can then be directed and controlled with the application of a specialized metasurface. This method has the advantage of redirecting energy rather than discarding it, making such metasurfaces both smaller and more efficient.

They emphasized that such a device relies on established theory and would be possible to design and fabricate using existing technology.

“The fundamental principles are understood. We have the basic theoretical tools to make the design. Now we need to find clever ideas for how to make it happen,” said Greffet.

Source: “Controlling spontaneous emission with metasurfaces,” by J.-J. Greffet and B. Vest, APL Engineering Physics (2026). The article can be accessed at https://doi.org/10.1063/5.0349577 .