Passive Acoustic Subwavelength Resonator (PASR) - Phase II

We propose a Phase II program to continue the development of a Passive Acoustic Subwavelength Resonator (PASR) intended for deployment in undersea environments. The PASR concept is designed to be deeply subwavelength and passively scatter acoustic fields at resonance within a tunable spectral band, potentially with tailored directivity.  The PASR functional components are stiff compared to water and are expected to preserve their functionality over a range of ocean depths. Phase II will provide a reduction to practice of the PASR concept using acoustic target scattering and pressure testing of at-scale prototypes submerged underwater.  Phase II deliverables will include design optimization tools, experimental demonstrations of tunable subwavelength resonance from an object a tenth of a wavelength in size or less, and paradigms for understanding directional scattering form subwavelength acousto-elastic components.  Potential applications include vector sensing, low-power acoustic communication nodes, and enhanced scattering directivity useful for the collimation of projected sound.