Engineers and physicists from the Delft Technical University in the Netherlands have unveiled a groundbreaking development in the realm of nanotechnology. Through their research, they have successfully created a microphone that is 200 times smaller than conventional models, while still delivering comparable sound quality.
Unlike traditional microphones that utilize a vibrating membrane, this innovative device features a graphene sheet – an ultra-thin layer of carbon consisting of just one atom in thickness.
The functionality of this microphone is rooted in a unique design, where the graphene sheet is stretched over a silicon cylinder that is filled with air. The operation of the microphone relies on the use of lasers: one laser induces vibrations in the membrane at its resonance frequency, while a second laser detects variations in this frequency caused by incoming sound waves, thereby converting sound into an electrical signal.
In a demonstration of the microphone’s capabilities, researchers used it to record a musical theme from the popular video game Super Mario Bros. The results indicated that the device could capture sound within a frequency range similar to that of traditional microphones, although the quality of the recordings still falls slightly behind established technologies.
The active part of the microphone can have a diameter as small as 10 micrometers. By miniaturizing the microphone to such an extent, it becomes possible to house multiple components in the space previously occupied by a single standard microphone. This advancement opens up new possibilities for mobile devices, enabling improved noise reduction and precise sound localization.
However, Professor Anthony Kent from Nottingham University points out a crucial challenge: the laser system required to detect audio signals from the graphene membrane is currently larger in size than the graphene sheet itself. For the technology to be viable for widespread use in smartphones, further reduction of the entire system’s size is essential.
Despite this limitation, this development marks a significant leap forward in audio technology and has promising applications not only in mobile devices but also in various other fields where compact and highly sensitive microphones are needed.