Giant Rabi splitting in metal/semiconductor

nanohybrids

J. Bellessa, C. Symonds, J.C. Plenet, A. Lemaitre, K. Vinck, D. Felbacq

Laboratoire de Physique de la Matière Condensée et Nanostructure, Lyon, FranceLaboratoire de Photonique et Nanostructures, Marcoussis, FranceGroupement d’Etude des Semiconducteurs, Montpellier, France

• Properties of surface plasmons• Description of surface plasmons• Plasmons in strong coupling

• Hybridisation localised plasmon/exciton• Localised plasmon in nanodisks• Nanodisks with organic semiconductor

• Particularities of the hybrid states• Inhomogeneous broadenings• Geometrical effects

• Conclusion

Outline

Surface plasmon

• Interface metal / dielectric material

• Damping in the metal

Dielectric

Metal

100nm

20nm

2D 0D nanoparticules1D plasmon guide

W. L. Barnes et al., Nature, 418, 306 (2002)

Properties of surface plasmons

Properties of surface plasmons

Delocalised plasmon in strong coupling

D.E. Gomez et al. Nano Lett. 10 274 (2010)

Strong interaction between plasmons and :

• Aggregated dyes

• Laser dyes such as Rhodamine 6G

• Semiconductor nanocrystals arrays : CdSe dots under a thin silver film

Rabi splitting of 112 meV

T.K. Hakala et al. PRL 103 053602 (2009)

J. Bellessa, C. Bonnand, J.C. Plenet, J. Mugnier., PRL 93, 36404 (2004)

Weak coupling : Luminescence enhancement with nanoantennas

Plasmon in strong coupling

J. Dintinger et al. Phys. Rev. B 71, 035424 (2005)

Plasmons in nanoshells

N. T. Fofang et al. Nanoletters 8 10 3481 (2008)

GOLD

Y. Sugawara et al. PRL 97, 266808 (2006)

Metallic nanostructures

Holes and voids in metallic structures

Properties of surface plasmons

Localised plasmons

• Discrete Plasmon resonance

• Distance between the disks 200nm• Low inhomogeneous broadening

300nm

Hybridisation localised plasmon/exciton

100 120 140 1600

2

4

6

8

10

12

14

16

Num

ber

of p

artic

les

Size (nm)

Ag Nanodisks control of the environment and size

Bare plasmon resonances

Transmission of nanodisks

Plasmon resonances

energy : size dependant

linewidth 150meV

No plasmon overlapping

100 120 140 160 180 200 2201.61.71.81.92.02.12.22.32.42.5

Tra

nsm

issi

on

Nanodisk diameter (nm)

143 nm121 nm

111 nm

1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.80.0

0.2

0.4

0.6

0.8

1.0

(b)

Energy (eV)

Ene

rgy

(eV

)

(a)

50 100

20

40

60

80

100

120

Hybridisation localised plasmon/exciton

Nanodisks with TDBC

Three transmission dips

TDBC absorption

two size dependant dips

Uncoupled regions Bare TDBC

1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.60.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Ab

sorp

tion

(a

. u

.)T

ran

smis

sio

n

Energy (eV)

121 nm143 nm

111 nm

1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6

(b)

(a)

Hybridisation localised plasmon/exciton

Nanodisks covered with a TDBC layer

Two levels model

• Formation of localised plasmon/ exciton mixed states

excexc

plpl

iE

ikEH

2/

2/)(

Eplasmon Eexcitonħ

1.8

2.0

2.2

2.4

LMSBare exciton

Nanoparticle diameter (nm)

LMS

(a)

E (

eV)

(b)

Bare plasmon

100 120 140 160 180 20040

60

80

100

120

140

160

180

200

UMS

UMS

Line

wid

th (

meV

)

Hybridisation localised plasmon/exciton

Formation of polaritons• Rabi splitting depends on TDBC thickness

• FDTD simulations• Rabi energy 450meV

20% of the transition energy

100 120 140 160 180 200 220

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

En

erg

y (e

V)

Nanodisk diameter (nm)

(b)

Nanodisk diameter (nm)

450meV

1 TDBC layer 2 TDBC layers

100 120 140 160 180 200 220

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

En

erg

y (e

V)

Hybridisation localised plasmon/exciton

J. Bellesa et al. Phys. Rev. B 80, 33303 (2009)

Homogeneous and inhomogeneous broadenings

• In microcavities

• In nanoparticles

Particularities of the hybrid states

N

N N

photon Excitons

?N. F. Fofang et al. Nanolett. 2008, 8 (10), 3481

Strong couplingERabi<inhomogène

plasmonsexciton

Distance between disks

Large modification of the bare plasmons

Diffractive effects

Rabi energy roughly unchanged

1500 2000 2500

0.3

0.6

0.9

Energie (meV)

250nm 185nm 235nm 210nm

Particularities of the hybrid states

Conclusion

• Localized plasmon/exciton hybridization

• Rabi splitting of 450 meV (20% transition energy)

• Model system for cylindrical nanoparticles with controlled size and environment