A Local Nanofiber-Optic Ear

Abstract

The development of acoustic sensors that are compact, have simple read-out mechanisms, and have geometries that enable them to be inserted/embedded deep in materials is of great interest for acoustic-based imaging technologies and novel analytical instruments. Fiber-optic-based detectors are the most logical choice to satisfy these demands, but scaling down the size to sub-micrometer dimensions and uncovering transduction mechanisms that can be more robust than interferometric techniques in dynamic environments has been challenging. In this work, we demonstrate a non-interference-based acoustic ear that utilizes the movement of plasmonic nanoparticles embedded in the near field of a nanofiber optic. The modulated optical signal induced by sound waves can be read-out through transmission through the nanofiber or by tracking the scattering of the nanoparticles in the far field. By utilizing a thin, compressible cladding on the nanofibers, acoustic intensities of <10–8 W/m2 can be detected by the devices ove...