Researchers have demonstrated, for the first time, a mechanically flexible silver mesh that is visibly transparent, and allows infrared wireless optical communication and efficiently shields electromagnetic interference in the X band portion of the microwave radio region.
Optical communication channels are important to the operation of many devices and are often used for remote sensing and detection.
This could have special importance in the medical world as electromagnetic interference shielding is often used to prevent electromagnetic radiation from devices from interfering with each other and affecting device performance.
“Many conventional transparent electromagnetic interference shields allow only visible light signals through,” said research team leader Liu Yang from Zhejiang University in China. “However, visible wavelengths are not well suited for optical communication, especially free-space — or wireless — optical communication, because of the huge amount of background noise.”
In the journal Optical Materials Express, the researchers describe their new mesh. They show that when combined with transparent silicone and polyethylene, it can achieve a high average electromagnetic shielding effectiveness of 26.2 dB in the X band with good optical transmittance at a wide range of wavelengths, including those in the infrared.
“We take the advantage of the ultrabroad transparency and low haze of a metallic micromesh to demonstrate efficient electromagnetic shielding, visible transparency and high-quality free-space optical communication,” said Yang. “Sandwiching the mesh between transparent materials improves the chemical stability and mechanical flexibility of the silver mesh while also imparting a self-cleaning quality. These properties will enable our silver mesh to be applied widely both indoors and outdoors, even on corrosive and free-form surfaces.”
Image: Liu Yang, Zhejiang University