Graphene audio system mimics bat communication

The devices could be used to transmit signals underwater, but with far more fidelity than current sonar or ultrasound devices, according to the team. It is also claimed that the system could be used to communicate through solid objects such as steel, which electromagnetic waves are unable to penetrate.

“Sea mammals and bats use high-frequency sound for echolocation and communication, but humans just haven’t fully exploited that before, in my opinion, because the technology has not been there,” said UC Berkeley physicist Alex Zettl, one of the lead researchers on the project.

“Until now, we have not had good wideband ultrasound transmitters or receivers. These new devices are a technology opportunity.”

The research, published this week in the Proceedings of the National Academy of Sciences, began two years ago with Berkeley postdoctoral fellow Qin Zhou building a set of speakers using a sheet of graphene for the diaphragm.

Graphene membranes are just one atom thick and are significantly more efficient than the paper or plastic used in conventional speakers. The graphene speakers convert over 99 per cent of inputted energy into sound, compared to eight 8 per cent in off-the-shelf sound equipment.