Granted Patent B2

US 12,469,479 · App. 18/225,224 · Granted Nov 11, 2025

Inventors: Yuning Guo (Boulder, CO); Massimo Ruzzene (Boulder, CO); Matheus Rosa (Boulder, CO)

Assignee: The Regents of the University of Colorado, a body corporate

G10K11/162G10K11/30

Abstract

Claims (35)

1 . An acoustic device, comprising:

a three-dimensional phononic crystal having cubic symmetry and comprising:

a first region filled with a first material; and

a second region that is the solid complement of the first region, the second region being filled with a solid material that is different from the first material;

wherein:

a boundary between the first and second regions is shaped as a single gyroid surface with constant mean curvature and not pinched off; and

a second volume of the second region is greater than a first volume of the first region.

2 . The acoustic device of claim 1 , the first material comprising a fluid.

3 . The acoustic device of claim 2 , the solid material being stiffer than the fluid.

4 . The acoustic device of claim 2 , the fluid comprising a gas.

5 . The acoustic device of claim 4 , the gas comprising air.

6 . The acoustic device of claim 1 , the three-dimensional phononic crystal supporting topological surface states.

7 . The acoustic device of claim 1 , the three-dimensional phononic crystal exhibiting a band structure that has at least one degenerate point that is protected by nonsymmorphic symmetry.

8 . The acoustic device of claim 1 , the solid material fully filling a solid complement of a unit cell of the three-dimensional phononic crystal.

9 . The acoustic device of claim 1 , the gyroid surface being mathematically approximated by the isosurface function:

F =cos( {tilde over (x)} )sin( {tilde over (y)} )+cos( {tilde over (y)} )sin( {tilde over (z)} )+cos( {tilde over (z)} )sin( {tilde over (x)} ),

wherein:

{tilde over (x)}=2πx/a, {tilde over (y)}=2πy/a, and {tilde over (z)}=2πz/a are scaled spatial coordinates along the x, y, and z axes, respectively, of a unit cell of the three-dimensional phononic crystal;

a is a length of the unit cell; and

F is a constant such that 0≤|F|<F po , F po being the value of F at which the pinch-off regime begins.

10 . The acoustic device of claim 9 , the constant F having a value such that 1≤|F|<F po .

11 . The acoustic device of claim 1 , a volume fraction of the three-dimensional phononic crystal being greater than 50% and less than 97.1%.

12 . The acoustic device of claim 1 , the solid material comprising plastic, metal, glass, ceramic, polymer, carbon fiber, or resin, or any combination thereof.

13 . The acoustic device of claim 1 , wherein:

the three-dimensional phononic crystal is bounded by a plurality of external surfaces; and

the acoustic device exhibits acoustic negative refraction where two of the plurality of external surfaces meet.

14 . The acoustic device of claim 1 , wherein:

the three-dimensional phononic crystal is bounded by a first external surface;

the acoustic device further comprises an acoustic material bounded by a second external surface; and

the second external surface directly contacts the first external surface to form an acoustic interface therebetween.

15 . A method, comprising coupling an acoustic wave into the acoustic device of claim 1 to excite a topological surface state of the three-dimensional phononic crystal.

16 . A method, comprising guiding an acoustic wave along a surface of the acoustic device of claim 1 .

17 . A method, comprising energy harvesting with the acoustic device of claim 1 .

18 . A method comprising coupling an acoustic wave into the acoustic device of claim 14 to excite a topological surface state of the acoustic interface.

19 . A method comprising guiding an acoustic wave along the acoustic interface of the acoustic device of claim 14 .

Assignments (2)

Continuity (2)

References Cited (17)