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SFB & START
p. 1
Olomouc 2005
Status and Challenges
In Molecule Interferometry
Markus ArndtInstitut für ExperimentalphysikUniversität Wien
SFB & START
p. 2
C60
Short reminder: Far-field diffraction at a nanograting
C Sourc e60
Collim ation
5 µm 5 µ m
1 .33 m1.13 m
Gra tingVeloci tySelect or Ioniz ation Lase r
C Source60
Collimation
5 µm
1.33 m
IonizationLaserVelocitySelector
5 µm
1.13 m
Grating
-150 -100 -50 0 50 100 150
100
200
300
400
num
bero
fdet
ecte
dm
olec
ules
Detector position (µm)
1000
2000
3000
4000
M. Arndt et al., Nature 401, 680 (1999).
O. Nairz, M. Arndt, A. Zeilinger, AJP 71, 319 (2003).
Without v-selection
With v-selection
Interferencedemonstrated !InterferenceInterferencedemonstrated !demonstrated !
SFB & START
p. 3
Building blocks of molecular quantum nanophysics
Applications
DecoherenceCoherent
Manipulation
Detectors
Sources
Molecule Interferometry
SFB & START
p. 5
Talbot-Lau Near-Field interferometry
n is a t i o nla s e rg
o ld g ra t ie r i
0
3
2
1
max min
max min
I IVI I
−=
+
Visibility:
Shift of 3 grating (µm)
rd
C70
Phys. Rev. Lett. 88, 100404 (2002).
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p. 6
Pattern Formation in a Talbot-Lau Interferometer
Number of Moleculesbehind 3rd Grating
Interference generates a molecular pattern. Its period equals the period of the gratings.
3. Grating: Scanning Mask
IncoherentMolecular beam
1. Grating:Coherence Prepar.
2. Grating: Diffraction
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p. 7
Prove of the wave nature:Variation of interference contrast with v (λ)
24018014012010790 80 0
10
20
30
40
50vi
sibi
lity
[%]
v [m/s]
experimentquant. w. van der Waalsquant. w. Casimir-Polderquant. w/o potentialclass. w. van der Waalsclass. w/o potential
SFB & START
p. 8
Interferometry with Porphyrins: C44H30N4 (TPP)
58 59 60 61 62 63
4000
6000
8000
10000
12000
14000
Visibility = 35 %
position of 3rd grating (μm)
spectrometer background level
coun
ts in
40
s
150 160 170 180 190 200 210 220 230 240
5
10
15
20
25
30
35
40 experimental data quantum expectation classical expectation
visi
bilit
y (%
)
mean velocity (m/s)
~ 2
nm
Question:
Influence of symmetry on interference contrast?
Answer:
Nearly perfect wave behavior!
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p. 9
Current world record in mass & complexity
C60 F48
1632 amu !108 Atoms in a single object !Isomeres with different symmetries
45.5 46.0 46.5 47.0 47.5 48.0 48.50
1000
2000
3000
4000
5000
dete
ktie
rte M
olek
üle
Position des 3. Gitters (µm)
Also here: Quantum interference !
Phys. Rev. Lett 91, 90408 (2003).
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p. 10
Decoherence & Phase Shifts studied …
Chirality?
Elect. & Mag.Dipol Moments
Inertial Phase Shifts
Polarizability(vdW)
ThermalRadiation
Collisions
Decoherence& Phase Shifts
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p. 11
Collisions withbackground molecules
0 2 4 6 8 10 12 14 16 18
0,2
0,4
0,6
0,8
1,0
Nor
mal
ised
Vis
ibilit
y
Pressure (in 10-7 mbar)
Decoherence: Collisions
Phys. Rev. Lett. 90, 160401 (2003).
Physics Today (2005).
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p. 12
Decoherence: Thermally induced radiation
Thermal photon emission
Heating &T- measurement
00 1 22 3 44 5 66 7 88 9 10100,0
0,2
0,4
0,6
0,8
1,01540 2580 2880 2930 2940
Incident Laser Power (W)
Nor
mal
ised
Vis
ibilit
y
Mean microcanonical Temperature (K)
NATURE 427, 711–714 (2004).
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p. 13
Novel Molecules: Similar mass but different physical properties…
TPP with electric dipole moment (COOH, …)
TPP with magnetic moment (Rare earths, …)
Question:
Molecule/Grating interaction: Dephasing ?
Predictions for proteins ?
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p. 15
Sources in the lab …
Electrospray(ESI)
Laser Desorption III
(JETLD)
Laser Desorption II
(TLD)
Laser Desorption I
(MALDI)
EffusiveVapor
MolecularBeam
Sources
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p. 17
Thermal SourcePerfluorinated Hydro-carbons
M = 2934 amu, C68H36NOSi2F105
Atoms/Molecule: 213
Extension: 4 x 3x 2 nm3
Dipole moment: ~ 9 Debye
Polarizability: ~ 100 Å3
Velocity: 80 m/s
M = 2934 amu, C68H36NOSi2F105
Atoms/Molecule: 213
Extension: 4 x 3x 2 nm3
Dipole moment: ~ 9 Debye
Polarizability: ~ 100 Å3
Velocity: 80 m/s
N,NN,N--Bis[3Bis[3--[tris(2[tris(2--perfluorooctylethyl)silyl]propylperfluorooctylethyl)silyl]propyl]]--trifluoroacetamidetrifluoroacetamide
Count rate: OK for Interferometry !
Detection: EI-Ionization QMS
Count rate: OK for Interferometry !
Detection: EI-Ionization QMS
1400 1600 1800 2000 2200 2400 2600 2800 3000
02x104
4x104
6x104
8x104
1x105
1x105
1x105
2x105M-R
MM-CF3M-COCF3
Cou
nt ra
te (c
ps)
mass / charge (u/e)
SFB & START
p. 18
Can we go even further ?Thermal Beams of Fullerene derivates !
Our current „source record“
m ~ 7000 u, v = 80 m/s m ~ 7000 u, v = 80 m/s
InsulinInsulin
≥≥5000 5500 6000 6500 7000 7500
01020304050607080
x=10x=9
x=8
x=7
C60[(CF2)11CF3]x
coun
t(100
0 s-1
)
mass (u)Only 6 side chains shown
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p. 20
Jet-expanded laser desorption (JETLD)
Neutral & directed beams of biomoleculesExcellent velocity selection (1:1000)
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p. 21
Laser desorption & Multiphoton ionisationIntense neutral beams of biomolecules detected !
Amino acids: Tryptophan
0 50 100 150 2000
1
2
3
4
5
6Carrier gas: Argon @ 2.8 barSignal/Noise: 5.9V/0.012V = 490
Sign
al (V
)
m/z (u/e)
0 400 800 1200 1600 20000.0
0.5
1.0
1.5
2.0Carrier gas: Argon @ 3.8 barSignal / Noise: 1.5V / 0.006V = 250
Polypeptide: Gramicidin~ 1800 u
Sig
nal (
V)
m/z (u/e)
Polypeptide: Gramicidin
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Molecule detectors in the lab …
UHV STM/AFM
Fluroescence Detection
Laser ionization &
TOF-MS
EI-ionization& QMS
Thermal ionization
Molecule Detectors
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p. 24
3rd grating position [nm]
heig
ht [μ
m]
Inte
nsity
[arb
. uni
ts]
0 500 1000 1500 2000 2500
0
100
200
400
500
700
800
900
1050
1150
1250140
160
180
200
220
240
260
280
300
320AA
BB
CC
DD
A Porphyrin experiment (TPP)
New Journal of Physics (11/2005).
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Advantages of Mec(anically) Mag(nified) Imaging:
Scalability !The efficiency improves with particle size!
Horizontal surface positionEncodes grating positionMagnification arbitrarily large, here 4500 x ‚Immune‘ to surface diffusion
Vertical surface positionEncodes molecule velocity Simultaneous recording of all velocities: extreme stabilityFavorable for distinguishing quantum from classical fringes
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p. 27
G1 G2 G3
Slit sourcearray
Scanning mask
Diffraction
G1 G2
Slit sourcearray
ScreenDiffraction
Deposition of Interferograms:Molecular Nanopatterns (in preparation …)
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From curiosity to curious applications ?!
SPM
C60Si(111)
Identified, post-processed with Scanning Probe Microscopy
Non-trivial patterns with added grating motions & new masks
Structures with down to 50/100 nm features/periods
Composed of single (functional) molecules (1- 10 nm sized)
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p. 30
Vacuum setup completed … STM/AFM being tested
Interferometer chamber Sample Transfer UHV STM/AFM
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p. 31
Summary & Outlook
Applications
DecoherenceCoherent
Manipulation
Detectors
Sources
Molecule Interferometry
SPM
C60Si(111)
00 1 22 3 44 5 66 7 88 9 10100,0
0,2
0,4
0,6
0,8
1,01540 2580 2880 2930 2940
Incident Laser Power (W)
Nor
mal
ised
Vis
ibilit
y
Mean microcanonical Temperature (K)
3rd grating position [nm]
heig
ht [μ
m]
Inte
nsity
[arb
. uni
ts]
0 500 1000 1500 2000 2500
0
100
200
400
500
700
800
900
1050
1150
1250140
160
180
200
220
240
260
280
300
320
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p. 32
The Vienna team on Molecular Quantum Optics
L. Hackermüller
E. ReigerA. StiborS. Deachapunya
M. Berninger
A. Stefanov A. Zeilinger
S. Gerlich G. Kiesewetter
M. Arndt
Former postdocs:Former postdocs:
Fabienne GoldfarbFabienne Goldfarb
Klaus HornbergerKlaus Hornberger
BjBjöörn Brezgerrn Brezger
Former PhD:Former PhD:
Olaf NairzOlaf Nairz
Former Diploma studentsFormer Diploma students
Julian Voss AndreaeJulian Voss Andreae
Julia PetschinkaJulia Petschinka
Stefan UttenthalerStefan Uttenthaler
H. UlbrichtA. Major