Ultrafast

diffraction with single electrons

F. Kirchner, S. Lahme, M. Aidelsburger, A. Gliserin, M. Walbran, C. Weninger,

F. Krausz, P. Baum

MPQ-LMU Laboratory for Attosecond

& High-Field Physics

UESDM –

December 13, 2012

Funding:Rudolf-Kaiser-Foundation, European Research Council, Munich

Center for

Advanced

Photonics

2

Single electron

pulses

3

Atoms and electrons

in motion

Baum, Yang, Zewail, Science 318, 788 (2007)

Movement

of atoms/nuclei

femto-

to picoseconds

Movement

of electron

density

attoseconds?

4

Examples

of electron

dynamics: iodine

Baum and Zewail, Chem. Phys. 366, 2 (2009)for 100%excitation

5

Experimental approach

• Ti:sapphire

oscillator: 5 MHz, 500 nJ

• tunable rep.-rate down to 128 kHz

• focus diameter on cathode: few microns

• 0.1 to 10 electrons per pulse

• water-cooled magn. lens in vacuum

6

Tailored excitation of metallic photocathodes

M. Aidelsburger, et al., PNAS, 107, 19714 (2010)

7

Tailored excitation of metallic photocathodes

M. Aidelsburger, et al., PNAS, 107, 19714 (2010)

8

Tailored excitation of metallic photocathodes

M. Aidelsburger, et al., PNAS, 107, 19714 (2010)

9

Microwave cavity

A. Gliserin, et al, New Journal of Physics 14, 073055 (2012)

10

Microwave cavity

A. Gliserin, et al, New Journal of Physics 14, 073055 (2012)

11

Microwave

generation

/ synchronization

F. Kiewiet, et al., Nucl. Instrum. Methods Phys. Res. A, 484, 619 (2002)

Phase locked

loop

voltage-controlled

oscillator

(PLL-VCO)

„Direct“

microwave

extraction

12

Characterization in the energy domain

• Wien

filter

New Journal of Phys. 14, 073055 (2012)

• High-resolution ToF

spectrometersub-1eV resolution

at 30 keV

Drift tube design

13

Temporal distortions

in magnetic

lenses

C. Weninger and P. Baum, Ultramicroscopy, 113, 145 (2012)

14

‘Isochronic’

magnetic lenses

Simulation results

C. Weninger and P. Baum, Ultramicroscopy, 113, 145 (2012)

17

Conclusion

Summary:

•

Single electron pulses•

Tunable excitation of photocathode

•

Microwave compression•

‘Isochronic’ magnetic lenses•

High spatial coherence

Drawbacks:

•

Reversible processes •

Sample relaxation/damage at high repetition rates

Perspective:

•

Study atomic motions in solid state samples •

Expand electron diffraction to study electron density in motion