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Controlling the interaction between light and matter confined in nanoscale. Leonardo de S. Menezes Departamento de Física Universidade Federal de Pernambuco 50670-901 Recife-PE, Brasil. lmenezes@df.ufpe.br www.df.ufpe.br/~lmenezes. - PowerPoint PPT Presentation
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Controlling the interaction between light and matter
confined in nanoscale
Leonardo de S. MenezesDepartamento de Física
Universidade Federal de Pernambuco50670-901 Recife-PE, Brasil
lmenezes@df.ufpe.brwww.df.ufpe.br/~lmenezes
Limits and Interfaces in Sciences / Kumboldt-KollegSão Paulo-SP, 28th - 30th October 2009
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1. Introduction2. Scanning near-field optical microscope (SNOM)
probe for controlling Raman microlaser action3. SNOM probe as a tool for controlling the
interaction of a nanoscopic light emitter with confined electromagnetic field
Outline of the talk
Motivation Using scanning probe tech-niques (SNOM) for controlling and manipulating confined light in microresonators, as well as to control the interaction of single nanoparticles with it.
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1. Introduction
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St. Paul´s cathedral, LondonLord Rayleigh, 1878
33 m
60 µm15 µm
· Easily produced by melting an optical fiber with a CO2 laser.
· Diameters from 20 m to 200 m.· Q factors up to 1010.· May store photons for some s.· Comparison: tuning fork 550 Hz,
same Q: oscillates for 4 days!!!· Modal volume V~3003
· Evanescent field allows the external coupling.
Braginsky et al., Phys. Lett. A 137, 393 (1989); L. Collot et al., Eur. Phys. Lett. 23, 327 (1993).
· Light is trapped in a whispering gallery mode by successive total internal reflections, travel-ling in a great circle along the cavity's perimeter.
Microspheres as optical cavities
100 m
Represent optical resonatorswith ultra-high Q-factors and small mode volumes.
~33 m
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Experimental setupSpectroscopy of the microspheres´ eigenmodes
Typical spectrum measured byabsorption and scattering
DiodeLase r
Pho
todi
ode
Pho
todi
ode
DiodeLase r
F iber toP
MT
F iber toP
MT
3D3D3D3D
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Experimental setup…
Constant distance (~10 nm) between the microsphere sur-face and the SNOM tip via a shear force control loop.
Tip-limited (~50 nm) optical resolution.
Allows getting a topogra-phical image.
Scanning Near-field Optical Microscopy
20mm
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2. Scanning optical near-field probe for controlling Raman
microlaser action
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For Q = 109, Pthreshold = 4.3 W world record!
=70mQ=3108
=795nm
4 mm
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br Controlling ultralow threshold Raman microlasing action
Near-field probe
1D scan + laser scanned
Pump mode (@ 795 nm) Laser mode (@ 814 nm)
Tip reduces the Q-factor of the WGM laser threshold increases
A. Mazzei et al., Appl. Phys. Lett. 89, 101105 (2006).
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3. Controlled and efficient photon transfer betweentwo single nanoemitters
mediated by WGMs
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Controlled coupling with a single dye-doped bead
PMTSpectrometerCCD
532 nmPump laser
N an o partic le
N ea r-fie ld p robe
Fluorescence microscope images of a single 200 nm dye-doped bead attached to a SNOM tip
Without notch filter
Withnotch filter
606 608 610200
400
600
Inte
nsity
[a.u
.]Wavelength [nm ]
FSR
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br Coupling of a singlenanoemitter to WGMs
PM T
75 80 85 90 95 100 105 110 6
8
10
12
14
16
18
20
22
24
Inte
nsity
(a. u
.)
Angle (degrees)
0 4 8 12 16 20 24 28 D istance [µm ]
200 nm
=85 µm
0
1
3
shea
rfor
cear
ea
2
4
shea
rfor
cear
ea
D is tance from bead to sphere surface [µm ] 0.0 0.2 0.4 0.6 0.8 1.0
Inte
nsity
[a.u
.]
PM T
200 nm in diameter dye-doped bead
S. Götzinger et al., Nano Lett. 6, 1151 (2006).
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br Confocal laser scanning micros-cope + dip coated microspheres
Pho
todi
ode
D iode Laser
3D
Fiber t oP
MT
3D
CC
D
3D
APD
F ilte r
F ibe r co up ledC o llim a to r
Spec
trom
eter
PM
T
O bje c tive
Galvo-drives
F ilte r
via scope
via prism
S. Götzinger et al., J. Opt. B: Quantum Semiclass. Opt. 6, 154 (2004).
Coupling of single semiconductor quantum dots:
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Heart of the experimental setupMultimode fiber connected to PMT Prism Collimating lens
Monomode fiber socket
Rotation stage
Monomode fiber with collimating and focus-sing lenses
Goniometer
Confocal microscope obejctive
Temperature stabilized Cu block
Stabilized 3D piezo stack
Cu tube with microsphere
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Cavity-mediated photon transfer
620 640 660 680
-30
0
30
60
90
120
150
Inten
sity [
a.u.]
Wavelength [nm]
In
tens
ity
(arb
. un
its)
Wavelength (nm)
620 640 660 680
0
50
100
150
200
250
Inte
nsity
[a.u
.]
Wavelength [nm]
I
nten
sity
(arb
. uni
ts)
Wavelength (nm)
Efficient photon transfer between two single nanoemitters
S. Götzinger et al., Nano Lett. 6, 1151 (2006).
Our calculations show that the transfer efficiency is 106 times larger that in free space!
WGM
Obj
ectiv
e
Spectrometer
exc=532nm
=35 m
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By using our setup, we have obtained cavity-mediated enhanced pho-ton transfer between two single nanoparticles.
We have used silica microspheres to observe an ultralow threshold Raman microlaser action and used a SNOM probe to control it.
We have shown how to fabricate microresonators presenting resonan-ces with ultrahigh quality factors, i.e., ultralong photon storage times.
Thank you for your attention!!!
And pretty close to our labs...
Baía dos Porcos, Fernando de Noronha-PE
A single nanoparticle was attached to the end of a near-field probe. The coupling to a high-Q WGM was obtained in a very controlled way.
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