Lund University

From Rydberg to Atto physic

Is matter a wave ?

Lund University

-33 000

Big Bang

1897/1911

Joseph John Thomson: Characterization of the electron as an elementary particleMax Planck: Explication of the Black body radiation - Planck constant

Albert Einstein: Explication of the Photoelectric effectErnest Rutherford : Discovery of nucleus

1884/1888

Johan Jakob Balmer & Johannes Rydberg: Discrete spectral lines in vapour lamp

Lund University

-33 000

Big Bang

1897/1911

Louis de Broglie: Wave-particle dualityWerner Heisenberg: uncertainty principleRudolf Schrödinger: Quantum mechanics

Wolgan Pauli: Exclusion principlePaul Dirac: Relativistic Quantum mechanics

Niels Bohr: First atomic model

Joseph John Thomson /Max Planck / Albert Einstein

Ernest Rutherford

1884/1888

Johan Jakob Balmer / Johannes Rydberg 1913

1924 /19

Lund University

19902000

19801970

1960

1940

Modern theory

Atoms,

Molecules,

Solid,

Surface

2010

Experiences on atoms

1950

Experiences on moleculesExperiences on surface

Laser visible (CW, ns, ps, fs

)

Synchrotron X-ray (ns, ps)

XUV

X-ray

(fs, as)

Experiences on nano

Louis de Broglie

Werner Heisenberg

Rudolf Schrodinger

Wolgan Pauli

Paul Dirac

Lund University

Natural time scale

Lund University

Dynamics in real time

To capture a moving object we need...

an exposure time /shutter faster than the motion !

StroboscopeSequential

Lund University

Electron dynamics – attosecond timescale

electron

XUV sourcewith temporal

coherenceion+

t<1fs E>2 eV

Heisenberg uncertainties

Lund University

step

-wis

e

dire

ct

Photoionization dynamics

1 photon 2 photon

dire

ct

step

-wis

e

Because everything is a wave, we can assign a phase to everything…

Interference between different ionization pathways arise from phase differences

Lund University

Experimental background

Lund University

Harmonic generation in a gas

generationGas (Ar)

focusingoptic

4 mJ, 35 fs800 nmTi:Saph

Attosecond pulses

filterwheel

Lund University

Harmonic generation in a gas

Corkum and Krausz, Nature physics 3, 381 (2007)

Lund University

Harmonics : Attosecond pulse trains

coupled, well-known phase!

Filtering one-two harmonics 100 meV bandwidth/harmonic fs timescale

Without filtering 10-20 eV bandwidth 260 as/pulse

Lund University

Pump-Probe experiments

IR Probe

focusingmirrorrecombination

mirror

delaystage

<30nm

4 mJ, 35 fs800 nmTi:Saph

ElectrondetectionXUV Pump

Lund University

Ionization with Harmonics + IR probe

Ip

harmonics

IR probesidebands

It is complicated…XUV pumpmainlines

Lund University

Ionization in valence shell

Lund University

Helium ionization

19

21

23

25

27

Har

mo

nic

ord

er

20 15 10 5 0 -5 -10 -15Delay (fs)

Ip

harmonics

He + hnH19-H27 He+ + e-(es )+ hnIR ,ed

1D Electron spectrometer

Paul et al., Science 192 1689 (2001)

RABITT

Lund University

Helium ionization

20 15 10 5 0 -5 -10 -15Delay (fs)

Freq.

Ampl

itude

DCcomp.

2w

FT(t)

He + hnH19-H21 He+ + e-(es )+ hnIR ,ed

FT(t)

FT(t)

FT(t)

Lund University

Helium ionization

Ampl

itude

DCcomp.

2w

FT(t)

He + hnH19-H21 He+ + e-(es )+ hnIR ,ed

ArgonHelium

F offset

(rad

)

Helium 3p

Helium 1s

What is happening?

Harmonic 15

Harmonic 17

Lund University

What do we measure?

i

ka

k

Measured: XUV + IR ionization

1ke

Measured: XUV

Lund University

Resonant ionization of helium

tuning to red

Ionization threshold

Swodoba et al. Phys Rev Lett 104,

103003 (2010)

Lund University

Ionization in valence and inner valence shells

Lund University

Unbound states

• free particle:

with

r

E

• potential present:

shift δ with respect to free particle

δ carries information about core region

Lund University

δ for different potentials

• short range potential: V=0, r > r0

matching conditions

• real potential: , r > r0

0

V

r0

r=>

0

V

r0

rscattering phase

Lund University

Scattering phaseand photoemission time delay

• One-Photon ionization:

phase of complex amplitude is scattering phase

• Group delay of an electron wave packet during photoemission optics: pulse propagation electron propagation:

Wigner time delay

1s

k

Lund University

Measurement principle

Ar

S modulated with harmonic-IR delay:

Lund University

What do we measure?

i

ka

k

ke

Wigner time delay

Interference:

Measured: XUV + IR ionization

Lund University

Compare experiment and approximation

Wigner time delay

Continuum-continuum contribution

Approximation

Experiment