New device may give humans ‘cat-like hearing’
New York: Scientists are developing an atomically thin device that could receive and transmit signals across a radio frequency range far greater than what humans can hear. The "drumhead" device being developed by researchers at Case Western Reserve University in the US is trillion times smaller in volume and 100,000 times thinner than the human eardrum.
The advance may lead to the next generation of ultra-low-power communications and sensory devices smaller and with greater detection and tuning ranges, researchers said.
Dynamic range is the ratio between the signal ceiling over the noise floor and is usually measured in decibels (dB). Human eardrums normally have dynamic range of about 60 to 100dB in the range of 10Hz to 10kHz, and our hearing quickly decreases outside this frequency range.
Other animals, such as the common house cat or beluga whale, can have comparable or even wider dynamic ranges in higher frequency bands. The vibrating nanoscale drumheads developed by Philip Feng, an associate professor at Case Western Reserve University, and his team are made of atomic layers of semiconductor crystals, with diameters only about one micron.
In a paper published in the journal Science Advances, the researchers demonstrated the capability of their key components - the atomic layer drumheads or resonators - at the smallest scale yet.
The work represents the highest reported dynamic range for vibrating transducers of their type, researchers said. To date, that range had only been attained by much larger transducers operating at much lower frequencies - like the human eardrum, for example, they said.
“What we have done here is to show that some ultimately miniaturised, atomically thin electromechanical drumhead resonators can offer remarkably broad dynamic range, up to 110 dB, at radio frequencies (RF) up to over 120 MHz,” Feng said.
“These dynamic ranges at RF are comparable to the broad dynamic range of human hearing capability in the audio bands," said Feng.