SOCOM wants ‘Acoustic Rainbow’ Tech for Silencing Drones

Researchers in Denmark have produced the acoustic equivalent of a rainbow, creating a structure that spatially decomposes sound into its component frequencies in free space. The new architecture could be used to make devices tailored to emit or receive certain frequencies of sound.

SOCOM wants ‘Acoustic Rainbow’ Tech for Silencing Drones
Visualization of the acoustic rainbow emitter (ARE) The morphogenetical topology optimization method shapes the scattering inclusions, shown as grey material. When the ARE is excited by a monopolar source emitting broad-band white noise, the radiated sound creates an acoustic rainbow. The source is positioned at the centre of the emitter (illustrated using white light) and driven with equal power at all frequencies from 7600 to 12800 Hz. In the figure, the experimentally measured acoustic output (far field) is mapped to the visible spectrum of light by its magnitude and frequency content in the full 360° surrounding the ARE. (Courtesy: Christiansen et al. Sci. Adv. eads7497)