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Olomouc 2005

Status and Challenges

In Molecule Interferometry

Markus ArndtInstitut für ExperimentalphysikUniversität Wien

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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 !

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Building blocks of molecular quantum nanophysics

Applications

DecoherenceCoherent

Manipulation

Detectors

Sources

Molecule Interferometry

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STATUS:

Interferometry with large molecules

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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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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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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

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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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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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Decoherence & Phase Shifts studied …

Chirality?

Elect. & Mag.Dipol Moments

Inertial Phase Shifts

Polarizability(vdW)

ThermalRadiation

Collisions

Decoherence& Phase Shifts

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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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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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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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Perspectives:

Developments for the near future

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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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STATUS: STATUS:

Effusive Sources up to 7000 uEffusive Sources up to 7000 u

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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)

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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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STATUS: STATUS:

JetJet--expanded Laser Desorptionexpanded Laser Desorption

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Jet-expanded laser desorption (JETLD)

Neutral & directed beams of biomoleculesExcellent velocity selection (1:1000)

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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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~ 2 nm

Mechanically Magnified Fluorescence Imaging

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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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Applications being explored…

Lithography

Metrology

Applications

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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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Mounting of the new Nanoimaging/fabrication lab

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Vacuum setup completed … STM/AFM being tested

Interferometer chamber Sample Transfer UHV STM/AFM

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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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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