Transcript PLMCN10-orals-15-Thursday-Th-12

Strong coupling between
Tamm Plasmon and
QW exciton
E. Homeyer, C. Symonds, A. Lemaitre* , J.C. Plenet, J. Bellessa
LPMCN (Laboratory of Physics of Condensed Mater and Nanostructures)
University Claude Bernard Lyon 1, Lyon, France
* LPN (Laboratory For Photonics and Nanostructures), Marcoussis, France
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Outline
• Introduction
• Plasmon in GaAs/GaAlAs heterostructures
• Samples
• Plasmon / heavy- and light-hole exciton mixing
• Room temperature experiments
• Tamm plasmon states
• Description of Tamm plasmons
• Emission of Tamm/exciton polaritons
• Conclusion
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Outline
• Introduction
• Plasmon in GaAs/GaAlAs heterostructures
• Samples
• Plasmon / heavy- and light-hole exciton mixing
• Room temperature experiments
• Tamm plasmon states
• Description of Tamm plasmons
• Emission of Tamm/exciton polaritons
• Conclusion
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Introduction
Surface plasmons
• Surface plasmon : Interface metal / dielectric material
Metal
Dielectric
– Damping ∟& // propagation
– TM Mode only
• Near a luminescent source (Dye or QW)
– Weak coupling regime
– Strong coupling regime
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Introduction
Plasmon in weak coupling regime
Objective : enhancement of the spontaneous emission rate
• For nanoparticles
• For active layers such as
GaN/InGaN QW
– Enhancement SER 92 x
A.Neogi, et al., Phys. Rev. B, 66,153305(2002)
– Enhancement PL 17 x
Enhancement PL : 2.5 x
Coupling efficiency 60%
A Akimov et al., Nature. 450, 402 (2007)
Okamoto K et al. Nature Mat. 3 (9) 601 (2004)
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Introduction
Plasmon in strong coupling
Strong interaction between plasmons and :
• Aggregated dyes.
• Laser dyes such as Rhodamine 6G
 Rabi splitting energies
up to 230 meV.
J. Bellessa, C. Bonnand, J.C. Plenet, J. Mugnier., PRL 93, 36404 (2004).
T.K. Hakala et al. PRL 103 053602 (2009)
• Semiconductor nanocrystals
arrays : CdSe dots under a thin
silver film
 Rabi splitting of 112 meV
D.E. Gomez et al. Nano Lett. 10 274 (2010)
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Outline
• Introduction
• Plasmon in GaAs/GaAlAs heterostructures
• Samples
• Plasmon / heavy- and light-hole exciton mixing
• Room temperature experiments
• Tamm plasmon states
• Description of Tamm plasmons
• Emission of Tamm/exciton polaritons
• Conclusion
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Plasmon in GaAs/GaAlAs heterostructures
Samples
Silver
Silver
QW (x5)
GaAs
Luminescence (arb. u.)
• Samples elaborated in collaboration with A. Lemaître (LPN)
1540
Xhh
Xlh
1550
1560
1570
Energy (meV)
• Decoupling with a silver grating : periodicity Λ = 250nm
Metal
Dielectric
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
1580
Plasmon in GaAs/GaAlAs heterostructures
Plasmon/heavy/light-exciton mixing
• Reflectometry at 77K
60°
θ
55°
50°
Reflectivity
45°
40°
35°
Anticrossing plasmon/Xlh
Strong coupling between SP
and excitons
30°
25°
Xhh
1500
1550
Xlh
1600
Energy (meV)
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Plasmon in GaAs/GaAlAs heterostructures
Plasmon/heavy/light-exciton mixing
• Dispersion relation
• Mixing of Xhh & Xlh
1,0
0,8
Xhh
Plasmon
Xhh
Plasmon
Xlh
Xlh
| |2
0,6
0,4
0,2
0,0
4,0
Polaritons :
-plasmon/
-heavy hole exciton/
-Light hole exciton
VXhh=22meV
VXlh=21meV
4,5
5,0
5,5
6,0
6,5
Wavevector (µm-1)
 E pl (k )  i plasmon

H 
1 / 2

 2 / 2

7,0
1 / 2
Eexclh  i Xlh
0
7,5
8,0


0

Eexc hh  i Xhh 
 2 / 2
J. Bellessa, C. Symonds, C. Meynaud, J.C. Plenet, E. Cambril, A. Miard, L. Ferlazzo, and A. Lemaitre. Phys. Rev. B 78, 205326 (2008).
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Plasmon in GaAs/GaAlAs heterostructures
Room temperature experiments
• Still strong coupling @ RT
 Rabi energy at resonance 20
meV
No polaritonic luminescence is present
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Outline
• Introduction
• Plasmon in GaAs/GaAlAs heterostructures
• Samples
• Plasmon / heavy- and light-hole exciton mixing
• Room temperature experiments
• Tamm plasmon states
• Description of Tamm plasmons
• Emission of Tamm/exciton polaritons
• Conclusion
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Tamm plasmon states
Description of Tamm plasmons
•
•
•
•
Surface mode
Bragg mirror / metal layer
Very narrow linewidth
Direct coupling to
radiative light
• TE and TM modes
• Deep penetration length
A. V. Kavokin, I. A. Shelykh, and G. Malpuech, Phys. Rev. B 72, 233102 2005.
M. E. Sasin, et al., Appl. Phys. Lett. 92, 251112 2008.
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Tamm plasmon states
Quantum wells in a Tamm structure
• Thick Bragg mirror to
reduce the linewidth
Silver film
15
Al0.05Ga0.95As
AlAs
GaAs substrate
25
• Silver film on top of
the structure 
Tamm plasmon mode
• Inclusion of 2
InGaAs/AlGaAs QWs
in the 15 last high
refractive index layers
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Tamm plasmon states
Reflectometry experiments
Energy (meV)
Reflectiviy
(Arb. units)
1430 1440 1450 1460 1470 1480
• Anticrossing between the
exciton and the Tamm
plasmon
Energy (meV)
1470
• Thin polariton lines
compared to the splitting
1450
1440
1430
Energy (meV)
• Rabi splitting : 12 meV
1460
(b)
(b)
1470
1460
• Simulations with a transfer
matrix method
1450
1440
1430
(c)
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
20 22 24 26 28 30 32
Tamm plasmon states
Luminescence of hybrid states
• Strong emission at the
low polariton energy
• Incoherent luminescence
• Emission in TE and TM
polarisations
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010
Conclusion
• Hybrid states plasmon/exciton in inorganic
semiconductors
• Plasmon/Xlh/Xhh interaction energies of
21 and 22 meV
• Emission of Tamm plasmon/exciton
polaritons
PLMCN 2010, Cuernavaca, Mexico - April 15th 2010