Quantum mechanics

Materials science

Reflector (photography)

Astrophysics

Slab

Acoustics

Wavelength

Magnitude (astronomy)

Lattice (music)

Physics

Hertz

Optics

Lattice constant

Condensed matter physics

Geophysics

Light source

Diffraction

Optoelectronics

Science

We have fabricated sonic crystals, based on the idea of localized resonant structures, that exhibit spectral gaps with a lattice constant two orders of magnitude smaller than the relevant wavelength. Disordered composites made from such localized resonant structures behave as a material with effective negative elastic constants and a total wave reflector within certain tunable sonic frequency ranges. A 2-centimeter slab of this composite material is shown to break the conventional mass-density law of sound transmission by one or more orders of magnitude at 400 hertz.

Locally Resonant Sonic Materials