Generation of twin photons in Triple Microcavities Jérôme TIGNON C. Diederichs, D. Taj, T. Lecomte, C. Ciuti, Ph. Roussignol, C. Delalande Laboratoire Pierre Aigrain (LPA), École Normale Supérieure, Paris, France A. Lemaître, J. Bloch, O. Mauguin, L. Largeau Laboratoire Photonique et Nanostructures (LPN), CNRS, Marcoussis, France C. Leyder, A. Bramati, E. Giacobino Laboratoire Kastler Brossel (LKB) Ecole Normale Supérieure, Paris, France
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Generation of twin photons in Triple Microcavities Jérôme TIGNON C. Diederichs, D. Taj, T. Lecomte, C. Ciuti, Ph. Roussignol, C. Delalande Laboratoire.
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Generation of twin photons in Triple Microcavities
Jérôme TIGNON
C. Diederichs, D. Taj, T. Lecomte, C. Ciuti, Ph. Roussignol,
C. Delalande
Laboratoire Pierre Aigrain (LPA),
École Normale Supérieure, Paris, France
A. Lemaître, J. Bloch, O. Mauguin, L. Largeau
Laboratoire Photonique et Nanostructures (LPN),
CNRS, Marcoussis, France
C. Leyder, A. Bramati, E. Giacobino
Laboratoire Kastler Brossel (LKB)Ecole Normale Supérieure, Paris, France
Motivations
Fundamental
Better understanding and control of light-matter interaction in semicond. nanostructures
Practical
Generating quantum correlated photons is the basis for quantum optics applications such as quantum cryptography.
Working systems rely on large and complex optical sources
Possibility to develop an integrated micro-generator of twin photons ?
Outline
Non-linear optics
Parametric conversion Phase matching OPOs
Light-matter interaction in semiconductors
Semiconductor microcavities Weak and Strong coupling regime OPO in single microcavities A triply resonant OPO in a VCSEL-like structure
o C. Ciuti et al., Phys. Rev. B 62, 4825 (2000)(théorie quantique)
o D. M. Whittaker et al., Phys. Rev. B 63, 193305 (2001)(théorie semi-classique)
Theory :
Gisin et al, Quantum cryptography, REV. MOD. PHYS. 74 (2002)
Motivations: -OPO
Source of twin photons ? quantum optics (quantum cryptography)
o Strong coupling regime required Low temperature (max 50 K)
o Idler emitted at very large angle + weakly coupled to outside
Inefficient collection for twin photons applications
o Pump injection at large angle No electrical injection with an integrated system
DRAWBACKS:
sp
i
What we want!
o Phase-matching without the strong coupling exciton / photon
Increase the temperature
o High idler intensity (at a smaller emission angle)
Efficient collection for twin photons applications
o Pump injection at 0°
Electrical injection possible
Micro-OPO in triple microcavities
New Design: a Triple Microcavity
C. Diederichs and J. Tignon, APL 87 (2005)
Coupling DBR 1
DBR GaAs/AlAs
-GaAs cavity 1
Substrate
-GaAs cavity 2
-GaAs cavity 3
DBR GaAs/AlAs
Coupling DBR 2
In0.07GaAs QW
Z growth axis
8m
In0.07GaAs QW
In0.07GaAs QW
Angle (degree)
Ene
rgy
(eV
)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Optical modes (transfer matrices simulation)
Cavity degeneracy lifted
For dual-cavities : see e.g. Stanley et al., APL 65 (1994) : strong coupling between 2 cavities Pellandini et al., APL 71 (1997) : dual- laser emission
Armitage et al., PRB 57 (1998) : polariton dispersion
Uncoupled cavities |Coupled cavities
21
4
R
RRc
Condition for 2 coupled cavities :
Photonics modes delocalized throughout the whole structure
Inclusion of QWs / Weak and Strong coupling regime
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Angle (degree)
Ene
rgy
(eV
)
Strong Coupling Weak Coupling
Strong exciton-photon regime
Six polariton modes
Cavity-mode degeneracy lifted
Three coupled photonic modes
Experimental setup
Triple microcavity 8m
90°
CW Ti:sa
850 nm
Bragg mirrors
subs
trate
Optical fiber
QW1 QW2 QW3
Sample Growth: LPN
Tuning of the photon modes
Single cavities
X
Spacer wedge along X by interruption of the rotation at 0°
X
Ecav
Triple cavity
Cavity 1 : interruption at 0° (X) Cavity 2 : no interruption Cavity 3 : interruption at 90° (Y)
X
Y
Ecav
X
C. Diederichs et al, NATURE 440 (2006)
OPO (a)
all beams @ 0°
energy conservation
-30 -25 -20 -15 -10 -5 0
1.460
1.465
1.470
1.475
signal
pump
idler
Ene
rgy
(eV
)
Angle (degree)
0 5 10 15 20 25 30
x 200
100.0
1659
2.751E4
4.562E58E5
T = 6 K
OPO (b)
idler: negative dispersion
momentum conservation
-30 -25 -20 -15 -10 -5 0
1.460
1.465
1.470
1.475
signal
pump
idler
Ene
rgy
(eV
)
Angle (degree)
0 5 10 15 20 25 30
x 200
100.0
1659
2.751E4
4.562E58E5
T = 6 K
C. Diederichs et al, NATURE 440 (2006)
1.460 1.465 1.470
0
1000
2000
3000
4000
5000
0
1
2
3
4
5
Inte
nsity
(a.
u.)
Idle
r
Pum
p
Sig
nal
x 10
00
Energy (eV)
Properties of the OPO
Below threshold : 2 kW/cm2
Above threshold : 3.2 kW/cm2
gain of 4800
narrowing of the signal and idler from 1 meV to below 200 eV
high conversion efficiency under cw excitation = 10-2
Phase-matching dependence
-1 0 1 2 3 4 5
0
5
x = 2Ep-E
s-E
i (meV)
Id
ler
inte
nsi
ty (
a.u
.)
-1 0 1 2 3 4 5
0
5
10
15
x = 2Ep-E
s-E
i (meV)
Sig
nal i
nten
sity
(a.
u.)
x : “phase-matching” parameter Strong non-linear emission of the signal and idler states only for x=0, i.e. for E=0, k=0 (phase-matching).
103 10410-2
100
102
104
OP
O
N
orm
aliz
ed in
tensi
ty (
a.u
.)
Pump Power (W/cm2)
signal idler
Power dependence (a)
OPO threshold : 2.4 kW/cm2
103 10410-2
100
102
104
LA
SE
R
OP
O
N
orm
aliz
ed in
tensi
ty (
a.u
.)
Pump Power (W/cm2)
signal idler Laser
Power dependence (b)
Lasing at 6 kW/cm2
Low OPO threshold
Out of phase-matching
Comments / saturation of the idler
- Idler at higher energy is degenerate with QW absorption continuum
- Idler (and not Signal) is subject to multiple parametric scattering
- Signal / Idler ratio important ?
- yes for quantum-noise measurements applications
- no if one counts coincidences (it just lowers the overal coincidence counting rate)