From individual to coupled metallic nanocavities
Adi Salomon, Yehiam Prior
Weizmann Institute of Science
Radoslaw Kolkowski, Marcin Zielenski, Joseph Zyss
ENS-Cachan
From individual to coupled metallic nanocavities
di Salomon, Yehiam Prior, Radoslaw Kolkowski, Marcin Zielenski, Joseph Zyss
WIS, ENS-Cachan
Nanocavities
In and
thin Symmetry
silver film
Strong
coupling
200nm
SHG measurements
• Coherent process
• Sensitive to symmetry
• Non linear process
Iy
.
Scanning of the SHG response – Individual Cavities
1000
10
900
20
800
30
700
40
600
50
500
60
400
70
300
80
200
90
100
ω
2ω
100
5 micron
20
40
60
80
100
0
Scanning of the SHG response – Individual Cavities
1500
0
200
700
5
600
y[nm]
400
1000
10
500
15
600
400
20
25
300
500
800
30
200
35
1000
100
40
5 micron
5
0
200
400
10
600
x [nm]
15
800
20
25
1000
30
0
Size Resonances – side length dependency
SHG(intergrated signal)
30000
25000
20000
15000
10000
5000
150
200
250
300
side length [nm]
Experimental conditions:
200nm Ag film evaporated on glass ,(n=1.5)
Excitation at : 940nm ;
SHG at 470nm
350
SHG(intergrated signal)
Size Resonances – side length dependency
10000
1000
150
200
250
side length [nm]
300
350
SHG(intergrated signal)
Size Resonances – side length dependency
10000
1000
150
200
250
side length [nm]
300
350
Size Resonances – Wavelength dependency
840
880
920
960
400
Counts/10 sec
Counts/10 sec
400
300
200
300
200
100
0
100
400
440
420
440
460
480
500
480
520
SH wavelength [nm]
SHG wavelength [nm]
triangular side length = 210nm, refractive index = 1.5
560
Coupling between Neighboring
Metallic NanoStructures
Coupling between metallic nanoparticles
In analogy to atoms hybridization
+ -
Energy
+ +
-
+
-
+ +
-
+
-
•
•
•
•
+ -
+ -
+ -
Gersten, J. I.; Nitzan, A. Surf Sci 1985, 158, (1-3), 165-189.
Sheikholeslami, S.; Jun, Y.-w.; Jain, P. K.; Alivisatos, A. P. Nano Letters 2010, 10, (7), 2655-2660
Rahmani, M.; Lei, D. Y.; Giannini, V.; Lukiyanchuk, B.; Ranjbar, M.; Liew, T. Y. F.; Hong, M. H.; Maier, S. A. Nano Lett 2012, 12, (4), 2101-2106
E. Prodan, C. Radloff, N. J. Halas,P. Nordlander Science 302, 419 (2003)
d=10nm
d=15nm
d=25nm
d
d=50nm
d=250nm
L. Gunnarsson et al. J. Phys. Chem. B 2005, 109, 1079-1087
Strong coupling between metallic nanocavities
• Can we design nanocavities that
couple to long distances ?
• How can we probe the degree of
coupling in these systems ?
Plasmonic Hybridization
500
nm
Strong coupling and Symmetry
 = -1, (2)
= -0.1, X correction = 2.3
Ag
120
120
90
90
2000
2000
1500
1500
60
60
1000
1000
150
150
30
30
500
500
3-fold symmetry
180
180
0
210
210
200nm
Reduced symmetrywhen coupled
330
330
240
240
300
300
270
270
?
0
SHG response at two orthogonal polarizations
1000
900
10
800
700
20
600
30
500
400
40
300
200
50
100
60
10
20
30
Triangle side length = 200nm
40
50
60
SHG response at two orthogonal polarizations
1000
900
10
800
700
20
600
30
500
400
40
300
50
200
200 nm
100
60
10
20
30
40
50
60
200 nm
Counts/sec
Counts/sec
SHG spectra with orthogonal input polarizations
SHG emission from coupled cavities
90
10000
120
60
8000
6000
150
30
4000
2000
180
0
210
200nm
330
240
300
270
200nm
The SHG emission is polarized !
Polarization sensitivity
5 microns
Fundamental beam polarization: horizontal
Can we probe the degree of coupling?
90
10000
120
60
8000
6000
150
30
4000
2000
180
0
210
330
240
300
270
Theoretical model
90
90
120
0.4
60
60
0.2
0.3
150
0.3
120
0.5
150
30
0.2
30
0.1
0.1
180
0
210
(a)
330
240
300
270
For three fold symmetry :
We define:
180
0
210
(b)
330
240
300
270
 = -0.57, 
(2)
Ag
120
= 0.2, X correction = 2.2
90 15000
60
10000
150
30
5000
180
0
rho= -0.5
210
330
240
300
270
Summary & Conclusions
• Size matters
• Strong coupling is mediated by SPP
1000
900
10
800
700
20
600
30
500
400
40
300
200
50
100
60
10
20
30
40
50
60
Future directions
• complementarity (Babinet’s principle)
between nanoparticles and nanocavities.
• What about chirality?
SHG from Metallic Nano Cavities
Joseph Zyss
Radoslaw Kolkowski
Yehiam Prior
Marcin Zeilenski
Thank you !
200 nm
1 micron
1 micron
200 nm
200 nm
200 nm
* Fabricated at WIS
1 micron
1 micron
Plasmonic Hybridization – In analogy to atoms hybridization
500
nm
* Triangular hole side length ~ 200nm
Babinet’s Principle
Case study: Array of individual triangles , side length 300nm
0
2
2
1
3
3
2
0
1
700
600
2
600
500
4
500
scaled in microns
scaled in microns
700
4
400
6
400
6
300
300
8
8
200
1010
100
0
0
2
2
4
6
8
4
6
scaled
in microns
scaled in microns
8
10
10
200
100
Mapping of the spots
More than 2 orders
of magnitude
for shaped triangle !
1
1
2
3
Non Inversion(
)/ Inversion symmetry (
SHG (Integrated signal)
10000
1000
100
50
100
150
200
250
side length [nm]
300
350
)
SHG emission patterns
90
2000
120
60
1500
1000
150
30
500
180
0
210
330
240
100nm
300
270
90
2500
120
60
2000
1500
150
30
1000
500
180
0
100nm
210
330
240
300
270
Polarization properties of an individual cavity
Figure 3
90
600
120
60
400
150
30
200
180
0
210
(a)
200nm
330
240
300
270
90
600
120
60
400
150
30
200
180
0
210
(b)
330
240
300
270
200nm
Strong coupling between nanostructures
• Can we consider nanocavities to be simply the complementary
structures to nanoparticles?
• Can we design nanostructures that lead to coherent coupling?
• How can we probe the amount of coupling in these systems ?
Theoretical model
 = -0.57, 
90
0.5
120
0.4
120
120
60
0.3
150
150
150
30
0.2
(2)
Ag
= 0.2, X correction = 2.2
90
90 0.3
90
15000
60
60
0.2
10000
60
0.2
30
30
5000
0.1
0.3
120
150
30
0.1
0.1
180
0
210
(a)
330
240
300
270
ρ=-1
180
180
00 180
210
210
(b)
330
330
240
240
300
300
270
270
ρ=-0.5
0
210
(c)
330
240
300
270
ρ=-0.1