Metasurfaces Now Master Thermal Radiation Control

Researchers from the Advanced Science Research Center at CUNY Graduate Center (CUNY ASRC) have made a groundbreaking discovery by showing that metasurfaces—two-dimensional nanostructured materials—can now precisely manage the optical properties of thermal radiation they generate themselves. This research, featured in Nature Nanotechnology, opens the door to innovative custom light sources with new, versatile applications across multiple scientific and technological fields.

Typically, thermal radiation is broad-spectrum and unpolarized, which restricts its application where specific light characteristics are needed. This contrasts sharply with laser light, which is highly controlled in terms of frequency, polarization, and direction, making it ideal for numerous advanced applications.

Metasurfaces offer a solution by manipulating electromagnetic waves through meticulously engineered nanoscale structures. While metasurfaces have traditionally been used to control laser light and required complex, expensive setups, the new goal is to enable metasurfaces to control their own thermal radiation without external lasers.

According to Adam Overvig, a key author of the study and now an assistant professor at Stevens Institute of Technology, their research is a major step toward creating metasurfaces that can internally regulate their thermal emission through heat-driven processes.

The team had earlier theorized that metasurfaces could shape their thermal radiation to produce specific frequencies, polarization, and wavefront shapes. Their latest findings experimentally validate these theories, demonstrating the capability to generate circularly polarized thermal radiation, surpassing previous limitations in polarization control.

The new design simplifies the metasurface to a single, patterned layer, facilitating easier fabrication and practical use. This advancement allows for full directional and characteristic control over thermal emission, which could be transformative for custom light sources in portable technologies like space exploration, field research, and military applications.

Additionally, the principles from this research might be applied to enhance light-emitting diodes (LEDs) and other common light sources. Future work aims to explore advanced thermal emission patterns, such as focusing emissions or creating thermal holograms, potentially revolutionizing the way custom light sources are designed and used.