In recent years, the confinement of light in open systems with no radiation leakage has raised great interest in the scientific community both due to its peculiar and intriguing physics and due to its important technological applications. In particular, materials with near-zero permittivity offer a unique opportunity for light localization, as they enable the formation of embedded eigenstates in core-shell systems with suppressed radiation loss. For all the solutions presented thus far in the literature, the exact suppression of the radiation leakage can occur only when the size of the resonator is delicately tuned. Surprisingly, here, it is shown that the tuning of the resonator radius may be unnecessary, and nonlocal metal spherical nanospheres of any size may support multiple embedded eigenstates with monopole-type symmetry.

1.
D. C.
Marinica
and
A. G.
Borisov
, “
Bound states in the continuum in photonics
,”
Phys. Rev. Lett.
100
,
183902
(
2008
).
2.
E. N.
Bulgakov
and
A. F.
Sadreev
, “
Resonance induced by a bound state in the continuum in a two-level nonlinear Fano-Anderson model
,”
Phys. Rev. B
80
,
115308
(
2009
).
3.
E. N.
Bulgakov
and
A. F.
Sadreev
, “
Bound states in a photonic Fabry–Perot resonator with nonlinear off-channel defects
,”
Phys. Rev. B
81
,
115128
(
2010
).
4.
Y.
Plotnik
,
O.
Peleg
,
F.
Dreisow
,
M.
Heinrich
,
S.
Nolte
,
A.
Szameit
, and
M.
Segev
, “
Experimental observation of optical bound states in the continuum
,”
Phys. Rev. Lett.
107
,
183901
(
2011
).
5.
M. I.
Molina
,
A. E.
Miroshnichenko
, and
Y. S.
Kivshar
, “
Surface bound states in the continuum
,”
Phys. Rev. Lett.
108
,
070401
(
2012
).
6.
J.
Lee
,
B.
Zhen
,
S.-L.
Chua
,
W.
Qiu
,
J. D.
Joannopoulos
,
M.
Soljacic
, and
O.
Shapira
, “
Observation and differentiation of unique high-Q optical resonances near zero wave vector in macroscopic photonic crystal slabs
,”
Phys. Rev. Lett.
109
,
067401
(
2012
).
7.
C. W.
Hsu
,
B.
Zhen
,
J.
Lee
,
S.-L.
Chua
,
S. G.
Johnson
,
J. D.
Joannopoulos
, and
M.
Soljacic
, “
Observation of trapped light within the radiation continuum
,”
Nature
499
,
188
191
(
2013
).
8.
E. N.
Bulgakov
and
A. F.
Sadreev
, “
Robust bound state in the continuum in a nonlinear microcavity embedded in a photonic crystal waveguide
,”
Opt. Lett.
39
,
5212
5215
(
2014
).
9.
E. N.
Bulgakov
,
K. N.
Pichugin
, and
A. F.
Sadreev
, “
All-optical light storage in bound states in the continuum and release by demand
,”
Opt. Express
23
,
22520
(
2015
).
10.
C. W.
Hsu
,
B.
Zhen
,
A. D.
Stone
,
J. D.
Joannopoulos
, and
M.
Soljacic
, “
Bound states in the continuum
,”
Nat. Rev. Mater.
1
,
16048
(
2016
).
11.
M.
Minkov
,
I. A. D.
Williamson
,
M.
Xiao
, and
S.
Fan
, “
Zero-index bound states in the continuum
,”
Phys. Rev. Lett.
121
,
263901
(
2018
).
12.
A.
Krasnok
and
A.
Alù
, “
Embedded scattering eigenstates using resonant metasurfaces
,”
J. Opt.
20
,
064002
(
2018
).
13.
Z.
Sakotic
,
A.
Krasnok
,
N.
Cselyuszka
,
N.
Jankovic
, and
A.
Alù
, “
Berreman embedded eigenstates for narrow-band absorption and thermal emission
,”
Phys. Rev. Appl.
13
,
064073
(
2020
).
14.
A.
Krasnok
,
D.
Baranov
,
H.
Li
,
M.-A.
Miri
,
F.
Monticone
, and
A.
Alù
, “
Anomalies in light scattering
,”
Adv. Opt. Photonics
11
,
892
(
2019
).
15.
J. V.
Neumann
and
E.
Wigner
, “
Über merkwürdige diskrete eigenwerte
,”
Phys. Z.
30
,
465
467
(
1929
).
16.
F. H.
Stillinger
and
D. R.
Herrick
, “
Bound states in the continuum
,”
Phys. Rev. A
11
,
446
(
1975
).
17.
F.
Capasso
,
C.
Sirtori
,
J.
Faist
,
D. L.
Sivco
,
S.-N. G.
Chu
, and
A. Y.
Cho
, “
Observation of an electronic bound state above a potential well
,”
Nature
358
,
565
567
(
1992
).
18.
I.
Hrebikova
,
L.
Jelinek
, and
M. G.
Silveirinha
, “
Embedded energy state in an open semiconductor heterostructure
,”
Phys. Rev. B
92
,
155303
(
2015
).
19.
M. G.
Silveirinha
, “
Trapping light in open plasmonic nanostructures
,”
Phys. Rev. A
89
,
023813
(
2014
).
20.
F.
Monticone
and
A.
Alù
, “
Embedded photonic eigenvalues in 3D nanostructures
,”
Phys. Rev. Lett.
112
,
213903
(
2014
).
21.
I.
Liberal
and
N.
Engheta
, “
Nonradiating and radiating modes excited by quantum emitters in open epsilon-near-zero cavities
,”
Sci. Adv.
2
,
e1600987
(
2016
).
22.
S.
Lannebère
and
M. G.
Silveirinha
, “
Optical meta-atom for localization of light with quantized energy
,”
Nat. Commun.
6
,
8766
(
2015
).
23.
S.
Silva
,
T. A.
Morgado
, and
M. G.
Silveirinha
, “
Discrete light spectrum of complex-shaped meta-atoms
,”
Radio Sci.
53
,
144
153
, (
2018
).
24.
F.
Monticone
,
H. M.
Doeleman
,
W. D.
Hollander
,
A. F.
Koenderink
, and
A.
Alù
, “
Trapping light in plain sight: Embedded photonic eigenstates in zero-index metamaterials
,”
Laser Photonics Rev.
12
,
1700220
(
2018
).
25.
F.
Monticone
,
D.
Sounas
,
A.
Krasnok
, and
A.
Alù
, “
Can a nonradiating mode be externally excited? Nonscattering states versus embedded eigenstates
,”
ACS Photonics
6
,
3108
(
2019
).
26.
S. V.
Silva
,
T. A.
Morgado
, and
M. G.
Silveirinha
, “
Multiple embedded eigenstates in nonlocal plasmonic nanostructures
,”
Phys. Rev. B
101
,
041106(R)
(
2020
).
27.
Z.
Hayran
and
F.
Monticone
, “
Capturing broadband light in a compact bound state in the continuum
,”
ACS Photonics
8
,
813
(
2021
).
28.
J. A.
Bittencourt
,
Fundamentals of Plasma Physics
, 3rd ed. (
Springer-Verlag
,
New York
,
2010
).
29.
A. R.
Melnyk
and
M. J.
Harrison
, “
Theory of optical excitation of plasmons in metals
,”
Phys. Rev. B
2
,
835
(
1970
).
30.
M.
Anderegg
,
B.
Feuerbacher
, and
B.
Fitton
, “
Optically excited longitudinal plasmons in potassium
,”
Phys. Rev. Lett.
27
,
1565
(
1971
).
31.
R.
Ruppin
, “
Optical properties of small metal spheres
,”
Phys. Rev. B
11
,
2871
(
1975
).
32.
R.
Ruppin
, “
Mie theory with spatial dispersion
,”
Opt. Commun.
30
(
3
),
380
382
(
1979
).
33.
C.
David
and
F. J. G.
de Abajo
, “
Spatial nonlocality in the optical response of metal nanoparticles
,”
J. Phys. Chem. C
115
(
40
),
19470
19475
(
2011
).
34.
G. W.
Hanson
,
E.
Forati
, and
M. G.
Silveirinha
, “
Modeling of spatially dispersive wire media: Transport representation, comparison with natural materials, and additional boundary conditions
,”
IEEE Trans. Antennas Propag.
60
,
4219
(
2012
).
35.
C.
David
,
N. A.
Mortensen
, and
J.
Christensen
, “
Perfect imaging, epsilon-near zero phenomena and waveguiding in the scope of nonlocal effects
,”
Sci. Rep.
3
,
2526
(
2013
).
36.
T.
Christensen
,
W.
Yan
,
S.
Raza
,
A. P.
Jauho
,
N. A.
Mortensen
, and
M.
Wubs
, “
Nonlocal response of metallic nanospheres probed by light, electrons, and atoms
,”
ACS Nano
8
(
2
),
1745
1758
(
2014
).
37.
S.
Raza
,
S. I.
Bozhevolnyi
,
M.
Wubs
, and
N. A.
Mortensen
, “
Nonlocal optical response in metallic nanostructures
,”
J. Phys.: Condens. Matter
27
,
183204
(
2015
).
38.
M.
Wubs
and
N. A.
Mortensen
, “
Nonlocal response in plasmonic nanostructures
,” in
Quantum Plasmonics
, edited by Sergey I. Bozhevolnyi,
Luis Martin-Moreno, Francisco Garcia-Vidal
, (Springer Series in Solid-State Sciences, 2017) p.
279
302
.
39.
J. R.
Maack
,
N. A.
Mortensen
, and
M.
Wubs
, “
Size-dependent nonlocal effects in plasmonic semiconductor particles
,”
Europhys. Lett.
119
,
17003
(
2017
).
40.
D.
Pines
and
D.
Bohm
, “
A collective description of electron interactions: II. Collective vs individual particle aspects of the interactions
,”
Phys. Rev.
85
,
338
(
1952
).
41.
V.
Agranovich
and
V.
Ginzburg
,
Spatial Dispersion in Crystal Optics and the Theory of Excitons
(
Wiley-Interscience
,
New York
,
1966
).
42.
M. G.
Silveirinha
and
S. I.
Maslovski
, “
Radiation from elementary sources in a uniaxial wire medium
,”
Phys. Rev. B
85
,
155125
(
2012
).
43.
F. J.
García de Abajo
, “
Optical excitations in electron microscopy
,”
Rev. Mod. Phys.
82
,
209
(
2010
).
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