Transcript Trion optical orientation - Weizmann Institute of Science

FEW-PHOTON OPTICAL NONLINEARITY IN A
QUANTUM DOT-PILLAR CAVITY DEVICE
V. Loo1, C. Arnold1, O. Gazzano1, A. Lemaître1, I. Sagnes1, O.
Krebs1, P. Voisin, P. Senellart1 and L. Lanco1,2
1. Laboratoire de Photonique et de Nanostructures - CNRS, Marcoussis, France
2. Université Paris Diderot – Paris 7, France
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Quantum information: how can we make photons interact?
Interaction between indistinguishable photons
Coalescence on a beamsplitter
Interaction between nearly simultaneous photons
A single-photon switch?
Interaction between delayed photons
A spin-photon interface?
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
or
Quantum information: how can we make photons interact?
Interaction between indistinguishable photons
Coalescence on a beamsplitter
Ultrabright sources of indistinguishable photons:
Gazzano et al, Nature Comm. 4, 1425 (2013)
Interaction between nearly simultaneous photons
A single-photon switch?
Interaction between delayed photons
A spin-photon interface?
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
or
Quantum information: how can we make photons interact?
Interaction between indistinguishable photons
Coalescence on a beamsplitter
Ultrabright sources of indistinguishable photons:
Gazzano et al, Nature Comm. 4, 1425 (2013)
Interaction between nearly simultaneous photons
A single-photon switch?
Optical nonlinearity with few-photon pulses:
Loo et al, PRL 109, 166806 (2012)
Interaction between delayed photons
A spin-photon interface?
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
or
Quantum information: how can we make photons interact?
Interaction between indistinguishable photons
Coalescence on a beamsplitter
Ultrabright sources of indistinguishable photons:
Gazzano et al, Nature Comm. 4, 1425 (2013)
Interaction between nearly simultaneous photons
A single-photon switch?
Optical nonlinearity with few-photon pulses:
Loo et al, PRL 109, 166806 (2012)
Interaction between delayed photons
A spin-photon interface?
Work in progress…
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
or
A quantum dot-cavity device
InGaAs/GaAs
quantum dot
Bragg
mirrors
conduction
Optical
mode
~ 1,35 eV
valence
Device :challenges
Controlled light-matter coupling
Near-unity coupling/collection efficiencies
Low optical losses
Low QD dephasing
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
(~ 930nm)
A quantum dot-cavity device
InGaAs/GaAs
quantum dot
Bragg
mirrors
conduction
Optical
mode
~ 1,35 eV
valence
Device :challenges
Controlled light-matter coupling
Near-unity coupling/collection efficiencies
Low optical losses
Low QD dephasing
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
(~ 930nm)
Deterministic coupling through in-situ lithography
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
In-situ lithography: why?
Spatial matching :
cavity
mode
QD at the maximum of
the field intensity
QD
Spectral matching :
EQD = Emode
micropillar
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Sample growth
MBE Growth
Aristide Lemaître
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Sample growth
MBE Growth
Aristide Lemaître
Random locations + random transition energies
E2
E1
E3
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
E4
Sample growth
Random micropillar: probability of success below 10-3
MBE Growth
Aristide Lemaître
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Sample growth
MBE Growth
Aristide Lemaître
Positive
photoresist
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Spatial matching…
Photoluminescence
EQD
PL Intensity (a.u.)
Laser
excitation
1340
1345
Selected QD transition
1350
1355
E (meV)
6
15
1210
12
4
910.0
9
610.0
6
310.0
3
x
y
piezoelectric actuators
0
10.00
µm
5
1500
7
6
5
µm
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
accuracy
50nm
Spatial matching…
Photoluminescence
Insulation
EQD
PL Intensity (a.u.)
Laser
excitation
1340
1345
Selected QD transition
1350
1355
E (meV)
6
15
1210
12
4
910.0
9
610.0
6
310.0
3
x
y
piezoelectric actuators
0
10.00
µm
5
1500
7
6
5
µm
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
accuracy
50nm
…and spectral matching
Photoluminescence
Insulation
EQD
PL Intensity (a.u.)
Laser
excitation
1340
1345
Selected QD transition
1350
1355
E (meV)
Mode Energy (meV)
Defining the appropriate radius
x
y
piezoelectric actuators
1,355
1355
1350
1,350
EM
EE
X ==EMODE
QD
1,345
1345
1340
1,340
0,5
0,5
1,0
1,0
1,5
1,5
radius (µm)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
2,0
2,0
Deterministically coupled devices
A. Dousse et al,
PRL 101, 267404 (2008)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Optical nonlinearity with few-photon pulses
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
The 2-level system: a highly nonlinear medium
Without a cavity:
QD
Efficiency = few %
With a cavity:
QD in excited state
1
Reflectivity
Reflectivity
QD in ground state
0
Photon energy
1
0
Photon energy
Transition: ~1 photon
inside the cavity
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
All-optical switching: recent results
Photonic crystals
Switch for ~ 1 photon
inside the cavity
N
n
N>100 with photonic crystals
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Switch for a single
incident photon?
A cavity-QD device : figures of merit
QD-cavity coupling strength: g
cavity damping rate:
k
= k0 + kloss
QD dephasing rate:
gdecoh =
gdecay
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
2
+ g*
A cavity-QD device : figures of merit
QD-cavity coupling strength: g
QD dephasing rate:
cavity damping rate:
k
= k0 + kloss
Total
Mirror
damping damping
gdecoh =
gdecay
Side
leakage
k0
hout =
k0 + kloss
Output-coupling
efficiency
Ideal:
hout =1
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
2
+ g*
A cavity-QD device : figures of merit
QD-cavity coupling strength: g
QD dephasing rate:
cavity damping rate:
k
= k0 + kloss
Total
Mirror
damping damping
gdecoh =
Side
leakage
k0
hout =
k0 + kloss
Output-coupling
efficiency
Total
dephasing
Ideal:
hout =1
gdecay
2
+ g*
Lifetime-limited Pure-dephasing
contribution
contribution
nc =
gdecoh gdecay
4 g2
Critical intracavity
photon number
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Ideal:
nc << 1
Experimental setup
Cryostat 4K-50K
Tunable
Laser (CW)
hin
Reference
APD
Measurement
APD
Input-coupling
efficiency
hin ~1 achievable
in micropillars
Arnold et al,
Applied Physics Letters 100, 111111 (2012)
To begin with : CW measurements
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Reflectivity spectra (low-power)
Temperature: T= 35.9 K
1.0
Unequal excitonic / photonic parts
Reflectivity
Reflectivity
Equal excitonic / photonic parts
Temperature: T= 34.8 K
0.9
0.8
0.7
1.3240 1.3241 1.3242
Photon energy (eV)
1.0
0.9
0.8
0.7
1.3240 1.3241 1.3242
Photon energy (eV)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Reflectivity map (experimental data)
1.0
44
cavity -like
42
0.9
38
QD-like
0.8
36
34
QD-like
0.7
32
30
cavity-like
1.3240
1.3241
0.6
1.3242
Photon energy (eV)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Reflectivity
Temperature (K)
40
Reflectivity
Reflectivity
Reflectivity
Giant optical nonlinearity – CW measurements
1.0
P0=1.1 nW
1.0
0.8
0.6
1.0
1.0
n = 0.0003
1.324
1.3241
1.3242
P0=11 nW
0.6
1.0
hin = 0.95
n = 0.0026
1.324
1.3241
1.3242
Output coupling hout =0.16
P0=36 nW
0.8
n = 0.02
1.324
1.3241
1.3242
P0=110 nW
0.6
1.0
0.8
0.6
Input coupling
0.8
0.8
0.6
P0=3.4 nW
n = 0.15
1.324
1.3241
1.3242
Critical photon number :
nc = 0.035
P0=340 nW
n<<nC : low-power limit
0.8
n = 1.5
1.324
1.3241
1.3242
Photon energy (eV)
0.6
n=7
1.324
1.3241
n>>nC : high-power limit
1.3242
Photon energy (eV)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
What about N?
Pulsed measurements
Ti:Sa
laser
N
single photon APD
Pulse width: 34 ps ~ 1/k
Fixed wavelength
Cryostat
single photon APD
Same beam shape
Reflectivity
Same input-coupling expected
1.0
hin = 0.95
0.8
0.6
1.324
1.3241
1.3242
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Few-photon nonlinearity threshold
0.90
V. Loo et al,
PRL
109, 166806 (2012)
Reflectivity
0.88
Nonlinear threshold:
8 incident photons / pulse
0.86
0.84
Factor 10 improvement
8 photons
0.82
Fit with quantum
master equation:
0.80
0.78 -1
10
101
100
102
103
Incident photons per pulse N
104
hin = 0.95
hout = 0.16
If hout ≈1: nonlinearity threshold at the single-photon level !
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Increasing the output-coupling
The standard way:
k0
hout = k + k
0
loss
Less mirror pairs:
→ higher
k0
Larger diameter:
→ lower
kloss
But decreased light-matter coupling…
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Increasing the output-coupling
The smart way:
adiabatic cavities
The standard way:
k0
hout = k + k
0
loss
Standard
Less mirror pairs:
→ higher
k0
Adiabatic
mirror
cavity
mirror
Larger diameter:
→ lower
kloss
Lermer et al. PRL 108, 057402 (2012)
Towards nonlinearity at the single-photon level…
…but deterministic single-photon switching ?
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Beyond the two-level system
« The maximal success probability for a single-photon router is 60% with a two-level system »
Barak Dayan, OASIS conference, Tel-Aviv, February 19th 2013
Nonlinearity in photonic molecules
Theory:
Bamba et al, PRA 83, 021802(R) (2011)
LPN: entangled photons
with photonic molecules
Dousse et al.
Nature 466, 217-220 (2010)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Beyond the two-level system
« The maximal success probability for a single-photon router is 60% with a two-level system »
Barak Dayan, OASIS conference, Tel-Aviv, February 19th 2013
Nonlinearity in photonic molecules
4-level system: spin in charged QDs
Theory:
Bamba et al, PRA 83, 021802(R) (2011)
LPN: entangled photons
with photonic molecules
s+
s-
Dousse et al.
Nature 466, 217-220 (2010)
~ 1 µs coherence
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
delayed photons!
Further perspectives
New in-situ processes for electrical control
Spin-photon entanglement
Theory: Hu et al, PRB 78, 085307 (2008)
Reflectivity
Real-time monitoring of single events
Logic gates with quantum light sources
1.0
0.9
0.8
0.7
0.6
RL
RE
0
200
400
600
Time (µs)
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël
Many thanks to:
Vivien Loo
Olivier
Gazzano
Christophe Arnold
Aristide
Lemaître
JCJC MIND,
P3N DELIGHT,
P3N CAFE
Isabelle
Sagnes
Pascale Senellart
Olivier
Krebs
SSQN
Paul
Voisin
QD-CQED
2013 OASIS Conference, February 19th – 20th, Tel-Aviv, Israël