Using quantum technology to ensure low-noise microphones

Experimental setup of the laser microphone Photo: University of Stuttgart / PI3, Florian Kaiser - Use of quantum light leads to a significant improvement in signal-to-noise ratio - [Picture: PI 3 / Florian Kaiser] Whether it's an online conference or a hearing aid, a high noise level in the microphones used, or significant background noise will disrupt any conversation, and better microphones are urgently needed. Researchers at the University of Stuttgart have now developed a quantum microphone that takes noise reduction to a whole new dimension. It was tested at Stuttgart's Olgahospital - with promising results. So far, the development of commercially available microphones has focused primarily on suppressing technical noise sources, such as signal amplification electronics. A research group led by Dr. Florian Kaiser at the Institute of Physics 3 at the University of Stuttgart has now gone one step further and investigated the fundamental limit up to which noise can be suppressed. They were able to show that using quantum technologies can push these limits. To this end, the group first developed a laser microphone similar to those used for monitoring industrial machinery and in espionage.