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Several Quantum-Optical Analogies in
Coupled Nanoantenna, Waveguide and
Metasurface
Jun-Jun Xiao
Harbin Institute of Technology, Shenzhen Graduate School
Xili, Shenzhen 518055, Guangdong Province, China
E-mail: [email protected]
IAS Winter School & Workshop on Advanced Concepts in Wave Physics: Topology and Parity-Time Symmetries, HKUST (2016.01.10-15)
Fano resonance
Toroidal moment
EIT
Optical topology
Insulator
……
….
Tamma et al., Nanoscale 5, 1592 (2013)
Zhang et al., Phys. Rev. Lett. 101, 047401 (2008)
Kaelberer et al., Science 330, 1510 (2010)
Bliokh et al., Nat. Photonics 9, 796 (2015)
Quantum-Optical Analogues
Bloch oscillation
Spin-dependent
optics
PT-symmetry
optics
Anderson localization
Zeno resonance
Gauge field optics
Outline
• Bloch oscillation in coupled nanoparticles and waveguides
− Wave-packet oscillation in time domain
− Bloch oscillation in spatial domain
• Fano resonance and EIT in nanoantenna and plasmonic waveguides
– Multiple Fano resonances by different order of electric antenna modes
– Magnetic and toroidal cavity modes in MDM nanodisk
– Double-EIT in plasmonic slot waveguides
– Controllable Fano/EIT in plasmonic-dielectric hybrid antenna
• PT-symmetry optics in coupled waveguides
• Absence of EP in finite-size waveguide array of apparently balanced gain/loss
• Summary
I. Bloch Oscillation, Fano Resonance & EIT
Zheng et al., J. App. Phys. 106, 113307 (2009)
Wave oscillation in graded nanoparticle chain
~ 11.8 ps
Bloch oscillation in graded waveguide array
Zheng et al., Phys. Rev. A 81, 033829 (2010)
Equation of motion:
Bloch Oscillation Breathing-like Oscillation
Miroshnichenko et al. Rev. Mod. Phys. 82., 2010
Joe et al. Phys. Scr. 74, 2006.
Classical analogy of Fano resonance & EIT
2 2
2 2
1 2 2 2 2 2
1 1 2 2
Af f i f
cf f i f f f i f
1. At the Fano dip resonance, the
“bright mode” is suppressed
2. Fano dip shows up near the
“dark mode” intrinsic frequency
3. Cross the Fano dip, “bright mode”
has abrupt phase variation
1| |C
Interference between
“bright” and “dark”
modes
U. Fano, Phys. Rev. 124, 1866 (1961)
Fano resonance induced by antenna modes
-- Reversal of optical binding force
E k
H
Homodimer:
---no Fano resonance
---no force reversal
Heterodimer:
----ED-EQ Fano resonance
----Reversal of binding force
Q. Zhang et al, Opt. Express 21, 6601 (2013)
E k
H
attraction
repulsion
Anti-bonding mode is completely dark
Multipole Fano resonances induced multiple BF reversals
Q. Zhang et al, Opt. Lett. 38, 4240 (2013)
Composite spoof localized surface plasmon (LSP)
R 33 mm
2 /d R N
0.15a d
1 0.4r R
2 0.5r R
20N
1 2 9.0g gn n
The spoof LSP resonance modes in the
composite resonator are derived from those
generated by the substructures
Spatially compact while spectrally efficient
Fano resonance in 2D composite spoof LSPs Complex resonance frequencies for the two
substructures are calculated
(1)2 0
(1) '
0
( )
( )
nn g
n
H k R fS n
H k R g
The relatively broad D-modes of
the two substructures interact with
each other and give rise to Fano-
like asymmetric line shape in the
spectrum
Qin, Xiao and Zhang et al., Opt. Lett. 41, 60 (2016)
A. Pors et al., Phys. Rev. Lett. 108, 223905 (2012)
Multimode competition and spectrum squeezing
1 7.787gn
At this particular point, two dipole
and one quadrupole resonance of
the two substructures come into
play, the effect of the quadrupole
resonance cannot be neglected
Fano resonance for 3D complex spoof LSPs (finite thickness)
1 0.3r R
2 0.4r R
0.3a d
t R
1 2.9gn
2 2gn
Transmission of slot waveguides with stub + resonators
Double EIT: Four-level atomic system
Z. Liu et al., Plamonics 10, 1057 (2015)
00 0 0 1 1
11 1 1 1 0 2 2
22 2 2 2 1
( )
( )
( )
j
e e
daj a e S j a
dt
daj a j a j a
dt
daj a j a
dt
0
j
eS S e a
St
S
Coherent plasmonic wave interference
CMT vs. FEM
22
0 0
1( )
e
e
ST
S j A
2
1 1 1/ [ ( ) ]A j B
2
2 2 2/ [ ( ) ]B j
EIT by interactions between Bragg gap and ‘polariton’ gap
Z. Liu et al., J. Opt. 18, 015005 (2016)
0Ti
e i
di
dt
aΩ Ξ Ξ a Γ S
i i i S C S Β a
1 2T
mi i i ia a aa
2 22 1 1
12 1 1
1
1
S S St r r
S S St r
M
12
1 1 e
iSt
S i
det 0BiK Le M IDispersion:
Transmission:
3 2 22
3 2 2
exp( ) 0
0 exp( )
S S Si
S S Si
M
2 1( )nM M M
222
1T M
Coupled mode theory
1
1 1
,e
e
Sr
S i
Single resonances case
Two-resonances case
Three-resonances case
2
2
1 10 2
21
2
1 ,e
e
St
Si
ii
2
2
10
1
1 .e
e
St
Si
i
1
2
10
1
,e
e
Sr
Si
i
1
2
1 10 2
21
2
.e
e
Sr
Si
ii
Plasmonic slot waveguide realization
Stopped by ‘polariton’ gap
II. Toroidal resonance and its interactions with other modes
Q. Zhang et at., ACS Photonics 2, 60 (2015)
Q. Zhang et al., J. Opt. Soc. Am. B 5, 1103 (2014)
E
K
H
Metal-Dielectric-Metal
Magnetic and toroidal cavity modes
anti-parallel going currents
Ez
Hx,y
EIT and Fano resonance induced by coupling between antenna mode and cavity modes
Delicately designed dipole antenna
Metal: Ag ------ antenna mode
Dielectric: ------ cavity mode
(different angular momentum)
load
90 , 50 , 20L nm R nm and d nm
Envelope: broad dipole resonance
sub-peak first dip second dip
Q. Zhang et al., Sci. Rep. 5, 17234 (2015)
=1load
=3load
=6load
=12load
=18load
Multipole decomposition in spherical basis
12
1 0 0(1) 2
0
2
1 0 0(1) 2
0
ˆ, sin
2 1 1
ˆ, sin
2 1 1
l
lm lm s
l
l
lm lm s
l
i kra Y d d
h kr E l l l
i krb Y d d
h kr E l l l
r E r
r H r
2 2
21
2 1l
s lm lm
l m l
C l a bk
(1)
lh spherical Hankel function
,lmY Spherical Harmonics
wave impendence in background
Multipole decomposition in Cartesian basis
4 4 5 6 6 6 62 22 2 2* *
03 3 4 5 5 5 5
2 2 4 2 2( Im( ) Re( )) / (8 )
3 3 3 3 20 20 15
e mIc c c c c c c
2
mP M P T T Q Q Μ R
3
3
2 3
3
3
2 3 2
1
1
2
1( ) 2
10
1 2( )
3
1
3
1[ ]
2
e
m
m
P J d ri
M d rc
T r r J d rc
Q r J J r d ri
Q r r d rc
R d r rc
r J
r J
r J
r J r J
r J
Note :
The SI form is just obtained by multiplying I in CGS
form by 0
1
4
2
0
2 I0SCS
ZC
E
2
0
ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ ˆ( ) ( ) ( ) [ ( )] ( )4 2 2
ikre mk e ik ik
E ikr
n P n M n n T n n n Q n n Q n
Multipole scattering decomposition: benchmark
High dielectric sphere benchmark
ED: electric dipole a1 MD: magnetic dipole b1 EQ: electric quadrupole a2 MQ: magnetic quadrupole b2 MH: magnetic hexapole b3
Numerical vs. Mie theory R 65
22
nm
E k
TM
D=250 nm
Pure silver disk w/o gap layer
EQ
ED
EH
Multipole scattering decomposition: Application
Two families of resonances: AM and CMs Dipole-toroidal Fano resonance suppresses the
bright electric antenna mode
Moments identified by multipole decomposition
Different far field scattering patterns
Coexistence of scattering suppression and enhancement
Spin-dependent emission control
Coupled oscillator model: bright + sub-bright + dark modes
( , , ) ( ) ( ) im
z gspE z a z f k e
( , , ) ~ ( ) ( )zE z AF z G
2( ') '
02 ( )i m me d m m
Tunable by geometry and loaded material
L = 90 nm, d = 20 nm , d = 20 nm 12
Adv. Mat. 2012, 24, OP136-OP142 ACS Nano, 2015, 10.1021/acsnano.5b01591
III. Absence of Exceptional Points in Coupled Waveguides
PT-symmetry and mode coalescence in 2D coupler
In optics
*n r n r
balanced gain/loss contrast 1 121 1
12 12 20
e
e
n ia ai d
n ia ak dz
2 2
12 1coupled en n
Non-Hermitian Hamiltonian
x -a a b -b
1n i1n i
0n
PT-symmetry and EP in 2D waveguide coupler
(1, 1) (1, -1)
( 1. ei0.52 ,1) (1. e i2.62 ,1)
Exceptional point (EP)
(1. ei1.57,1)
(2.62 ei1.57,1) (0.38 ei1.57,1) Complex conjugate
Real
Increasin
g
PT-symmetry in two coupled 3D waveguides
1 1
1 1
2 20
2 2
0 0
0 0
0 0
0 0
e L
e T
L e
T e
n ia a
n ib bi d
n ia ak dz
n ib b
0
p e p p p
p p e p p
a n i a ai dH
b n i b bk dz
p : Coupling strength for the longitudinal (p = L) and transverse (p = T) cases
, 3.5
1.5
0.2
0.5
A B
b
n ig
n
R m
d m
PT-symmetry in four coupled waveguides
1
1
1
e T
e T
iH
i
n
n
2
2
2 e
L
T
en iH
in
(TB, TB)
(LB, TB)
With EPs and phase transition
No EPs No phase transition Band 1,7
Band 3,4
Lattice symmetry Mode symmetry PT symmetry
Z. Z. Liu et al., (under review)
Phase rigidity
( ) ( )
1
( ) ( ) ( ) ( )
L R
k k
k R R R R
k k k k
r
0L R
l kkla
'R
kkl la
( )R
k ( )L
k normalized right (left) eigenvector
0L
l the original state
l the unit vector
Ding, Ma, Xiao, Zhang and Chan
arXiv:1509.06886 (2015)
Photonic cavity and magnetic resonance modes
Nanoantenna and optical-matter interaction
Metal-dielectric artificial metasurfaces
Magnetically controllable directional metasurface
Spoof SPP resonator and waveguide
Our Interests
• Financial Support
– NSFC(11004043, 11274083)
– 973 Program (2012CB921501)
– Guangdong Province NSF (2015A030313748)
– Shenzhen Municipal Science & Technology Plan (JCYJ20150513151706573, JSGG20150529153336124)
– Shenzhen Oversea Talent Plan (KQCX20120801093710373)
• Group Member (Ph.D Candidates)
• Collaborators
– Prof. K. W. Yu, Chinese University of Hong Kong
– Prof. D. Z. Han, Chongqing University
– Prof. L. Gao, Soochow University
– Prof. W. G. Liang, Fujian Inst. Res. Stuct. Matt.
– Prof. K. Y. Tao, Shenzhen University
Acknowledgements
X. M. Zhang Z. Z. Liu F. F. Qin Q. Zhang
Master Students
5-year development plan of HIT@Shenzhen
Expanding…
哈尔滨工业大学(深圳) with PG & UG