Scientists from China have demonstrated a smart “stealth material”, a meta-coating that controls the reflection and scattering of radiation. The physical essence of the coating is to suppress the electromagnetic scattering of the hidden object or to recreate the scattering properties to imitate the properties created by the surrounding background.

Researchers have demonstrated an autonomous aero-amphibious “stealth material” containing a set of modules for sensing, decision-making and execution that can maintain invisibility among an ever-changing background and neutralize external influences.

The physical breakthrough lies in the spatiotemporal modulation provided by tunable metasurfaces to shape the scattering field in both spatial and frequency domains. To intelligently control spatiotemporal metasurfaces, researchers applied stochastic evolutionary learning, which automatically approximates the optimal solution using maximum likelihood inference.

In one experiment, they applied this concept on an unmanned drone and demonstrated adaptive stealth with 95% similarity in three common landscapes (sea, land, and air). The team says their work expands the application of invisible surfaces to volatile objects.

According to the team, the coating can neutralize external influences while maintaining invisibility in dynamic conditions. A key advance is how the system manipulates tunable metasurfaces to shape the scattering field in space and frequency domains using spatiotemporal modulation.

The team developed a drone that performs scanning, decision-making and coverage operations. A special technique manipulates its surface in space and time, changing its appearance and behavior. This allows the drone to blend in or stand out in different environments such as water, land or air.

To make this work, the team used an intelligent learning system based on a generative neural network that manages the complex relationship between waves and metasurfaces. This helps the drone determine the best path for setup and choose the best possible behavior based on the possibilities. Scientists tested this on a working drone and made the drone nearly invisible in a variety of conditions.

The era of smart coatings and smart metasurfaces is just beginning. Efforts to achieve this goal have been carried out by optimizing photonic design, capturing hidden physics, and automating metadevices,” the study says. Source