Engineering news
The development, described in the journal Applied Physics Letters, was achieved by researchers at Chongqing University, Hong Kong University of Science and Technology, and Shenzhen Fantwave Tech. Co.
They created a layered glass material that allows for efficient sound transmission with no air ventilation. The window is comprised entirely of ordinary glass, resulting in an inexpensive and optically transparent material. It starts with a thick glass plate, which the researchers drilled holes into and filled with a thin, flat glass disk. They call these disks "decorations."
"It's almost totally transparent for human eyes, so we can distinguish objects across this meta-window," says Li Wang, one of the authors.
In its current configuration, the window has high levels of acoustic transmission for certain frequencies, and this can be tuned by adjusting the size of the circles. Adding multiple layers can broaden the range of frequencies, although there’s a trade off between doing that and overall transmission beyond the desired frequency range.
The design could have applications in chemistry, where gas explosion studies require a transparent partition that allows for sound waves to pass through but without airflow.
But the most important current application could be in designing Covid-secure partitions. Right now, customer service people are often placed behind plexiglass screens in an attempt to create a physical barrier to the coronavirus. Additional barriers would be more secure, but would make it hard for cashiers at banks or supermarkets to communicate with customers. This technology could allow that to happen more easily.