Acoustic topological systems explore topological behaviors of phononic crystals. Currently, most of the experimentally demonstrated acoustic topological systems are for airborne acoustic waves and work at or below the kHz frequency range. Here, we report an underwater acoustic topological waveguide that works at the MHz frequency range. The 2D topological waveguide was formed at the interface of two hexagonal lattices with different pillar radii that were fabricated with metal additive manufacturing. We demonstrated the existence of edge stages both numerically and in underwater experiments. Our work has potential applications in underwater/biomedical sensing, energy transport, and acoustofluidics.

1.
M. Z.
Hasan
and
C. L.
Kane
, “
Colloquium: Topological insulators
,”
Rev. Mod. Phys.
82
,
3045
(
2010
).
2.
H.
Ge
,
M.
Yang
,
C.
Ma
,
M.-H.
Lu
,
Y.-F.
Chen
,
N.
Fang
, and
P.
Sheng
, “
Breaking the barriers: Advances in acoustic functional materials
,”
Natl. Sci. Rev.
5
,
159
182
(
2018
).
3.
A. B.
Khanikaev
,
S. H.
Mousavi
,
W.-K.
Tse
,
M.
Kargarian
,
A. H.
MacDonald
, and
G.
Shvets
, “
Photonic topological insulators
,”
Nat. Mater.
12
,
233
239
(
2013
).
4.
T.
Ma
,
A. B.
Khanikaev
,
S. H.
Mousavi
, and
G.
Shvets
, “
Guiding electromagnetic waves around sharp corners: Topologically protected photonic transport in metawaveguides
,”
Phys. Rev. Lett.
114
,
127401
(
2015
).
5.
L.-H.
Wu
and
X.
Hu
, “
Scheme for achieving a topological photonic crystal by using dielectric material
,”
Phys. Rev. Lett.
114
,
223901
(
2015
).
6.
W.-J.
Chen
,
S.-J.
Jiang
,
X.-D.
Chen
,
B.
Zhu
,
L.
Zhou
,
J.-W.
Dong
, and
C. T.
Chan
, “
Experimental realization of photonic topological insulator in a uniaxial metacrystal waveguide
,”
Nat. Commun.
5
,
5782
(
2014
).
7.
Y.
Yang
,
Z.
Gao
,
H.
Xue
,
L.
Zhang
,
M.
He
,
Z.
Yang
,
R.
Singh
,
Y.
Chong
,
B.
Zhang
, and
H.
Chen
, “
Realization of a three-dimensional photonic topological insulator
,”
Nature
565
,
622
626
(
2019
).
8.
C.
He
,
X.
Ni
,
H.
Ge
,
X.-C.
Sun
,
Y.-B.
Chen
,
M.-H.
Lu
,
X.-P.
Liu
, and
Y.-F.
Chen
, “
Acoustic topological insulator and robust one-way sound transport
,”
Nat. Phys.
12
,
1124
1129
(
2016
).
9.
Z.
Zhang
,
Q.
Wei
,
Y.
Cheng
,
T.
Zhang
,
D.
Wu
, and
X.
Liu
, “
Topological creation of acoustic pseudospin multipoles in a flow-free symmetry-broken metamaterial lattice
,”
Phys. Rev. Lett.
118
,
084303
(
2017
).
10.
J.
Lu
,
C.
Qiu
,
L.
Ye
,
X.
Fan
,
M.
Ke
,
F.
Zhang
, and
Z.
Liu
, “
Observation of topological valley transport of sound in sonic crystals
,”
Nat. Phys.
13
,
369
374
(
2017
).
11.
H.
Dai
,
B.
Xia
, and
D.
Yu
, “
Temperature-controlled tunable underwater acoustic topological insulators
,”
J. Appl. Phys.
125
,
235105
(
2019
).
12.
H.
Dai
,
M.
Qian
,
J.
Jiao
,
B.
Xia
, and
D.
Yu
, “
Subwavelength acoustic topological edge states realized by zone folding and the role of boundaries selection
,”
J. Appl. Phys.
124
,
175107
(
2018
).
13.
A. B.
Khanikaev
,
R.
Fleury
,
S. H.
Mousavi
, and
A.
Alu
, “
Topologically robust sound propagation in an angular-momentum-biased graphene-like resonator lattice
,”
Nat. Commun.
6
,
8260
(
2015
).
14.
R.
Fleury
,
D. L.
Sounas
,
C. F.
Sieck
,
M. R.
Haberman
, and
A.
Alú
, “
Sound isolation and giant linear nonreciprocity in a compact acoustic circulator
,”
Science
343
,
516
519
(
2014
).
15.
X.
Zhang
,
H.-X.
Wang
,
Z.-K.
Lin
,
Y.
Tian
,
B.
Xie
,
M.-H.
Lu
,
Y.-F.
Chen
, and
J.-H.
Jiang
, “
Second-order topology and multidimensional topological transitions in sonic crystals
,”
Nat. Phys.
15
,
582
588
(
2019
).
16.
H.
Xue
,
Y.
Yang
,
F.
Gao
,
Y.
Chong
, and
B.
Zhang
, “
Acoustic higher-order topological insulator on a kagome lattice
,”
Nat. Mater.
18
,
108
112
(
2019
).
17.
K.
Sakoda
, “
Double Dirac cones in triangular-lattice metamaterials
,”
Opt. Express
20
,
9925
9939
(
2012
).
18.
Z.
Yu
,
Z.
Ren
, and
J.
Lee
, “
Phononic topological insulators based on six-petal holey silicon structures
,”
Sci. Rep.
9
,
1805
(
2019
).
19.
Y.
Shen
,
C.
Qiu
,
X.
Cai
,
L.
Ye
,
J.
Lu
,
M.
Ke
, and
Z.
Liu
, “
Valley-projected edge modes observed in underwater sonic crystals
,”
Appl. Phys. Lett.
114
,
023501
(
2019
).
20.
Z.-G.
Chen
,
X.
Ni
,
Y.
Wu
,
C.
He
,
X.-C.
Sun
,
L.-Y.
Zheng
,
M.-H.
Lu
, and
Y.-F.
Chen
, “
Accidental degeneracy of double Dirac cones in a phononic crystal
,”
Sci. Rep.
4
,
4613
(
2015
).
21.
A.
Dutt
,
M.
Minkov
,
I. A.
Williamson
, and
S.
Fan
, “
Higher-order topological insulators in synthetic dimensions
,”
Light: Sci. Appl.
9
,
131
(
2020
).
22.
Z.
Zhang
,
Y.
Tian
,
Y.
Wang
,
S.
Gao
,
Y.
Cheng
,
X.
Liu
, and
J.
Christensen
, “
Directional acoustic antennas based on Valley–Hall topological insulators
,”
Adv. Mater.
30
,
1803229
(
2018
).
23.
Z.-G.
Chen
and
Y.
Wu
, “
Tunable topological phononic crystals
,”
Phys. Rev. Appl.
5
,
054021
(
2016
).
24.
Z.
Zhu
,
X.
Huang
,
J.
Lu
,
M.
Yan
,
F.
Li
,
W.
Deng
, and
Z.
Liu
, “
Negative refraction and partition in acoustic valley materials of a square lattice
,”
Phys. Rev. Appl.
12
,
024007
(
2019
).
25.
H.
He
,
C.
Qiu
,
L.
Ye
,
X.
Cai
,
X.
Fan
,
M.
Ke
,
F.
Zhang
, and
Z.
Liu
, “
Topological negative refraction of surface acoustic waves in a Weyl phononic crystal
,”
Nature
560
,
61
64
(
2018
).
26.
X.
Zhang
,
M.
Xiao
,
Y.
Cheng
,
M.-H.
Lu
, and
J.
Christensen
, “
Topological sound
,”
Commun. Phys.
1
,
97
(
2018
).
27.
M.
Li
,
D.
Zhirihin
,
M.
Gorlach
,
X.
Ni
,
D.
Filonov
,
A.
Slobozhanyuk
,
A.
Alú
, and
A. B.
Khanikaev
, “
Higher-order topological states in photonic kagome crystals with long-range interactions
,”
Nat. Photonics
14
,
89
94
(
2020
).
28.
X.
Zhang
,
B.-Y.
Xie
,
H.-F.
Wang
,
X.
Xu
,
Y.
Tian
,
J.-H.
Jiang
,
M.-H.
Lu
, and
Y.-F.
Chen
, “
Dimensional hierarchy of higher-order topology in three-dimensional sonic crystals
,”
Nat. Commun.
10
,
5331
(
2019
).
29.
H.
Dai
,
B.
Xia
, and
D.
Yu
, “
Microparticles separation using acoustic topological insulators
,”
Appl. Phys. Lett.
119
,
111601
(
2021
).
30.
S.
Zheng
,
G.
Duan
, and
B.
Xia
, “
Underwater acoustic positioning based on valley-chirality locked beam of sonic system
,”
Int. J. Mech. Sci.
174
,
105463
(
2020
).
31.
S.-Y.
Yu
,
C.
He
,
Z.
Wang
,
F.-K.
Liu
,
X.-C.
Sun
,
Z.
Li
,
H.-Z.
Lu
,
M.-H.
Lu
,
X.-P.
Liu
, and
Y.-F.
Chen
, “
Elastic pseudospin transport for integratable topological phononic circuits
,”
Nat. Commun.
9
,
3072
(
2018
).
32.
J.
Mei
,
Z.
Chen
, and
Y.
Wu
, “
Pseudo-time-reversal symmetry and topological edge states in two-dimensional acoustic crystals
,”
Sci. Rep.
6
,
32752
(
2016
).
33.
M.
Sabatini Mattei
,
B.
Liu
,
G. A.
Mazzei Capote
,
Z.
Liu
,
B. G.
Hacha
,
T. A.
Osswald
,
Z.
Yu
, and
R. H.
Goldsmith
, “
3D printed polymer photonic topological insulators and their robustness to fabrication disorder
,” ChemRxiv (
2022
).
34.
G. A.
Mazzei Capote
,
M. C.
Montoya-Ospina
,
Z.
Liu
,
M. S.
Mattei
,
B.
Liu
,
A. P.
Delgado
,
Z.
Yu
,
R. H.
Goldsmith
, and
T. A.
Osswald
, “
Compounding a high dielectric constant thermoplastic material for production of microwave photonic crystals through additive manufacturing
,” ChemRxiv (
2021
).
35.
Z.-D.
Zhang
,
S.-Y.
Yu
,
H.
Ge
,
J.-Q.
Wang
,
H.-F.
Wang
,
K.-F.
Liu
,
T.
Wu
,
C.
He
,
M.-H.
Lu
, and
Y.-F.
Chen
, “
Topological surface acoustic waves
,”
Phys. Rev. Appl.
16
,
044008
(
2021
).
36.
M. T. A.
Khan
,
H.
Li
,
N. N. M.
Duong
,
A.
Blanco-Redondo
, and
S.
Atakaramians
, “
3D-printed terahertz topological waveguides
,”
Adv. Mater. Technol.
6
,
2100252
(
2021
).
37.
R. H.
Olsson
 III
and
I.
El-Kady
, “
Microfabricated phononic crystal devices and applications
,”
Meas. Sci. Technol.
20
,
012002
(
2009
).
38.
Z.
Zhang
,
Y.
Tian
,
Y.
Cheng
,
Q.
Wei
,
X.
Liu
, and
J.
Christensen
, “
Topological acoustic delay line
,”
Phys. Rev. Appl.
9
,
034032
(
2018
).
39.
Z.
Islam
,
A. K.
Agrawal
,
B.
Rankouhi
,
C.
Magnin
,
M. H.
Anderson
,
F. E.
Pfefferkorn
, and
D. J.
Thoma
, “
A high-throughput method to define additive manufacturing process parameters: Application to Haynes 282
,”
Metall. Mater. Trans. A
53
,
250
263
(
2022
).
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